Helensville was a New Zealand parliamentary electorate in the Auckland region, returning one Member of Parliament to the House of Representatives. The electorate was first established for the 1978 election, was abolished in 1984, and then reinstated for the 2002 election. The seat was won and held by John Key through his term as prime minister. Chris Penk of the National Party held the seat from the 2017 general election until its abolition in 2020, when it was replaced with the new Kaipara ki Mahurangi electorate, which Penk also retained.

The 1977 electoral redistribution, initiated by Robert Muldoon's National Government, was the most overtly political since the Representation Commission had been established through an amendment to the Representation Act in 1886. As part of the 1976 census, a large number of people failed to fill in an electoral re-registration card, and census staff had not been given the authority to insist on the card being completed. This had little practical effect for people on the general roll, but it transferred Māori to the general roll if the card was not handed in. Together with a northward shift of New Zealand's population, this resulted in five new electorates having to be created in the upper part of the North Island. The electoral redistribution was very disruptive, with 22 electorates being abolished, and 27 (including Helensville) being newly created or re-established. These changes came into effect for the 1978 election.

In the 1983 electoral redistribution, the Helensville electorate was abolished, and its area went to the West Auckland and Rodney electorates. Helensville was re-established in time for the 2002 election in response to continued high population growth in and around Auckland. It was formed from the northern flank of the Waitakere electorate with the addition of areas from the Rodney electorate around its southern boundary.

Helensville covers an area of the rapidly growing northern Auckland urban fringe, drawing Helensville and Kumeū from the former Rodney District, moving south to take in Paremoremo, Greenhithe and Albany from the former North Shore City, and finally tacking west to include Whenuapai, Hobsonville and West Harbour from the former Waitakere City.

The boundaries of the electorate changed significantly in the 2019/20 boundary review. Its northern boundary moved northward to become the same as the boundary between the Northland and Auckland local government regions, taking in part of the Northland electorate and all that part of Rodney electorate north of Waiwera, which is, by area, most of Rodney. On the other hand, an area running from Dairy Flat south to Paremoremo moved into Rodney, which is renamed the Whangaparāoa electorate. Helensville also gained the suburb of Westgate from the Upper Harbour electorate. It lost its southern section around the Waitakere Ranges to New Lynn. It was initially proposed that the electorate would keep the name Helensville, but after public submissions it became the Kaipara ki Mahurangi electorate.

In the 1978 election, the Helensville electorate was won by Dail Jones, who had been MP for the Waitemata electorate since the 1975 election. When the Helensville electorate was abolished in 1984, Jones stood in the West Auckland electorate in the 1984 election but was defeated by the Labour Party candidate, Jack Elder.

The Helensville electorate was re-established for the 2002 election. Newcomer John Key beat sitting Waitakere MP Brian Neeson to the National Party nomination and, in a tight year for his party, won the electorate by 1,705 votes in a split field when a disgruntled Neeson stood as an independent. At the same election, Dail Jones contested the electorate for New Zealand First. Helensville was partly rural and was wealthy beyond the national average, making it a safe National electorate, and Key was returned easily in 2005, 2008, 2011 and 2014 with large majorities. Key became National Party leader in 2006 and prime minister in 2008. In December 2016, he announced that he would retire from politics before the 2017 general election. He was replaced as Helensville MP by Chris Penk.

Key

  National   NZ First   Labour   ACT   Green

Election	Winner
1978 election		Dail Jones
1981 election
Electorate abolished in 1984 (see West Auckland and Rodney)
2002 election		John Key
2005 election
2008 election
2011 election
2014 election
2017 election		Chris Penk
(Electorate abolished in 2020; see Kaipara ki Mahurangi)

Members of Parliament elected from party lists in elections where that person also unsuccessfully contested the Helensville electorate. Unless otherwise stated, all MPs terms began and ended at general elections.

Election	Winner
2002 election		Dail Jones
2008		Dail Jones
2008 election		Darien Fenton
		David Garrett
2009		David Clendon
2014 election		Kennedy Graham

Jones entered Parliament in February 2008 following the resignation of Brian Donnelly
Garrett resigned in September 2010, and his list position was taken by Hilary Calvert
Clendon entered Parliament in October 2009 following the resignation of Sue Bradford

2017 general election: Helensville
Notes:		Blue background denotes the winner of the electorate vote. Pink background denotes a candidate elected from their party list. Yellow background denotes an electorate win by a list member, or other incumbent. A Y or N denotes status of any incumbent, win or lose respectively.
Party		Candidate		Votes	%	±%	Party votes	%	±%
	National	Chris Penk		21,704	56.12	−9.05	21,958	55.83	−2.56
	Labour	Kurt Taogaga		7,096	18.35	+5.66	10,012	25.45	+12.95
	Green	Hayley Holt		6,758	17.47	+4.75	2,971	7.55	−6.00
	NZ First	Helen Peterson		2,403	6.21	—	2,795	7.11	−0.25
	ACT	Alex Evans		284	0.73	-0.14	319	0.81	+0.07
	Conservative						87	0.22	−4.56
	Opportunities						799	2.03	—
	Legalise Cannabis						112	0.28	−0.17
	Māori Party						105	0.27	−0.27
	United Future						27	0.07	−0.19
	Outdoors						20	0.05	—
	Ban 1080						20	0.05	−0.09
	Mana Party						13	0.03	—
	People's Party						12	0.03	—
	Internet						9	0.02	—
	Democrats						7	0.02	−0.04
Informal votes				264			67
Total valid votes				38,676			39,333
	National hold		Majority	14,608	37.77	−14.69

2014 general election: Helensville
Notes:		Blue background denotes the winner of the electorate vote. Pink background denotes a candidate elected from their party list. Yellow background denotes an electorate win by a list member, or other incumbent. A Y or N denotes status of any incumbent, win or lose respectively.
Party		Candidate		Votes	%	±%	Party votes	%	±%
	National	Y John Key		22,720	65.17	−9.21	20,689	58.39	−7.40
	Green	Kennedy Graham		4,433	12.72	+5.36	4,801	13.55	+4.91
	Labour	Corie Haddock		4,425	12.69	−1.45	4,430	12.50	−1.85
	Internet	Laila Harré		1,315	3.77	+3.77
	Conservative	Deborah Dougherty		963	2.76	−0.07	1,692	4.78	+1.27
	Independent	Penny Bright		420	1.20	+1.20
	ACT	Phelan Pirrie		302	0.87	+0.36	262	0.74	−0.65
	Independent	Brendan Whyte		74	0.21	+0.21
	NZ First						2,608	7.36	+2.76
	Internet Mana						338	0.95	+0.78
	Māori Party						192	0.54	+0.02
	Legalise Cannabis						161	0.45	−0.04
	United Future						93	0.26	−0.20
	Ban 1080						48	0.14	+0.14
	Democrats						23	0.06	+0.04
	Independent Coalition						13	0.04	+0.04
	Civilian						8	0.02	+0.02
	Focus						3	0.01	+0.01
Informal votes				208			73
Total valid votes				34,860			35,434
Turnout				35,507	82.29	+5.65
	National hold		Majority	18,287	52.46	−7.78

2011 general election: Helensville
Notes:		Blue background denotes the winner of the electorate vote. Pink background denotes a candidate elected from their party list. Yellow background denotes an electorate win by a list member, or other incumbent. A Y or N denotes status of any incumbent, win or lose respectively.
Party		Candidate		Votes	%	±%	Party votes	%	±%
	National	Y John Key		26,011	74.38	+0.77	23,558	65.79	+2.09
	Labour	Jeremy Greenbrook-Held		4,945	14.14	-2.97	5,138	14.35	-4.11
	Green	Jeanette Elley		2,575	7.36	+1.41	3,094	8.64	+3.74
	Conservative	Richard Drayson		941	2.69	+2.69	1,258	3.51	+3.51
	Legalise Cannabis	Adrian McDermott		319	0.91	+0.91	174	0.49	+0.16
	ACT	Nick Kearney		180	0.51	0–1.72	499	1.39	-5.31
	NZ First						1,648	4.60	+2.06
	Māori Party						186	0.52	+0.03
	United Future						163	0.46	-0.33
	Mana						60	0.17	+0.17
	Libertarianz						19	0.05	-0.004
	Democrats						8	0.02	+0.001
	Alliance						4	0.01	-0.04
Informal votes				574			198
Total valid votes				34,971			35,809
	National hold		Majority	21,066	60.24	+3.74

Electorate (as at 11 November 2011): 46,983

2008 general election: Helensville
Notes:		Blue background denotes the winner of the electorate vote. Pink background denotes a candidate elected from their party list. Yellow background denotes an electorate win by a list member, or other incumbent. A Y or N denotes status of any incumbent, win or lose respectively.
Party		Candidate		Votes	%	±%	Party votes	%	±%
	National	Y John Key		26,771	73.61	+9.51	23,559	63.69	+8.60
	Labour	Darien Fenton		6,224	17.11	-9.77	6,826	18.45	-9.52
	Green	David Clendon		2,166	5.96	+5.79	1,814	4.90	+0.87
	ACT	David Garrett		811	2.23	+1.10	2,481	6.71	+4.36
	United Future	Angela Lovelock		309	0.85	-0.82	289	0.78	-1.69
	Libertarianz	Peter Osborne		89	0.24		21	0.06	+0.01
	NZ First						940	2.54	-3.34
	Progressive						195	0.53	-0.28
	Family Party						182	0.49
	Māori Party						182	0.49	+0.08
	Bill and Ben						170	0.46
	Legalise Cannabis						131	0.35	+0.16
	Kiwi						105	0.28
	Pacific						45	0.12
	Alliance						19	0.05	+0.02
	Workers Party						9	0.02
	Democrats						8	0.02	±0.00
	RAM						8	0.02
	RONZ						4	0.01	±0.00
Informal votes				251			110
Total valid votes				36,370			36,988
Turnout				37,298	82.27	-0.58
	National hold		Majority	20,547	56.49

2005 general election: Helensville
Notes:		Blue background denotes the winner of the electorate vote. Pink background denotes a candidate elected from their party list. Yellow background denotes an electorate win by a list member, or other incumbent. A Y or N denotes status of any incumbent, win or lose respectively.
Party		Candidate		Votes	%	±%	Party votes	%	±%
	National	Y John Key		22,008	64.10	+29.92	19,224	55.09	+29.28
	Labour	Judy Lawley		9,230	26.88	-0.24	9,761	27.97	-2.86
	NZ First	Dail Jones		1,400	4.08	-5.45	2,051	5.88	-6.06
	United Future	Andrea Deeth		573	1.67	-2.47	863	2.47	-5.82
	ACT	Stephen Langford-Tebby		389	1.13		821	2.35	-10.26
	Māori Party	Awa Hudson		359	1.05		142	0.41
	Progressive	Julian Aaron		318	0.93	-0.02	218	0.81	-0.08
	Direct Democracy	Helen Koster		58	0.17		11	0.03
	Green						1,407	4.03	-1.99
	Destiny						151	0.43
	Legalise Cannabis						66	0.19	-0.21
	Christian Heritage						48	0.14	-0.85
	Libertarianz						16	0.05
	Alliance						9	0.03	-1.00
	Democrats						8	0.02
	Family Rights						8	0.02
	99 MP						5	0.01
	RONZ						5	0.01
	One NZ						4	0.01	-0.04
Informal votes				253			110
Total valid votes				34,335			34,896
Turnout				35,222	82.85	+3.21
	National hold		Majority	12,778	37.22	+31.26

2002 general election: Helensville
Notes:		Blue background denotes the winner of the electorate vote. Pink background denotes a candidate elected from their party list. Yellow background denotes an electorate win by a list member, or other incumbent. A Y or N denotes status of any incumbent, win or lose respectively.
Party		Candidate		Votes	%	±%	Party votes	%	±%
	National	John Key		9,775	34.18		7,524	25.81
	Labour	Gary Russell		8,070	28.21		8,988	30.83
	Independent	Brian Neeson		5,644	19.73
	NZ First	Dail Jones		2,725	9.53		3,481	11.94
	United Future	Andrea Deeth		1,184	4.14		2,416	8.29
	Alliance	Helen MacKinlay		581	2.03		299	1.03
	Christian Heritage	David Simpkin		350	1.22		288	0.99
	Progressive	Clare Dickson		273	0.95		272	0.93
	ACT						3,676	12.61
	Green						1,755	6.02
	ORNZ						313	1.07
	Legalise Cannabis						118	0.40
	One NZ						15	0.05
	Mana Māori						10	0.03
	NMP						2	0.01
Informal votes				327			78
Total valid votes				28,602			29,157
Turnout				29,428	79.64
	National win new seat		Majority	1,705	5.96

1981 general election: Helensville

Party		Candidate	Votes	%	±%
	National	Dail Jones	8,242	35.85	−4.58
	Labour	Jack Elder	8,026	34.91	+0.71
	Social Credit	David Howes	6,718	29.22
Majority			216	0.93	−5.29
Turnout			22,986	89.05	+19.21
Registered electors			25,812

1978 general election: Helensville

Party		Candidate	Votes	%	±%
	National	Dail Jones	7,783	40.43
	Labour	Jack Elder	6,584	34.20
	Social Credit	Chris Lynch	4,510	23.43
	Values	Dennis Worley	370	1.92
Majority			1,199	6.22
Turnout			19,247	69.84
Registered electors			27,558

• McRobie, Alan (1989). Electoral Atlas of New Zealand. Wellington: GP Books. ISBN 0-477-01384-8.
• Norton, Clifford (1988). New Zealand Parliamentary Election Results 1946–1987: Occasional Publications No 1, Department of Political Science. Wellington: Victoria University of Wellington. ISBN 0-475-11200-8.
• Wilson, James Oakley (1985) [First published in 1913]. New Zealand Parliamentary Record, 1840–1984 (4th ed.). Wellington: V.R. Ward, Govt. Printer. OCLC 154283103.

• Electorate profile, Parliamentary Library

36°40′47″S 174°26′58″E / 36.6797°S 174.4494°E / -36.6797; 174.4494