Colin Craig is confident of winning the Rodney seat held by National MP Lockwood Smith after polling put him more than 10 points ahead of Dr Smith's successor, former policeman Mark Mitchell.
Mr Craig, a former Auckland mayoral candidate, yesterday said he would not, as expected, go head-to-head with John Banks for the Epsom seat, but instead had "followed his heart" to stand in Rodney.
"I've lived in Rodney, and my business involvement here has spanned more than 20 years," he said.
"Many of my family live here, and I'm passionate about getting things moving for everyone in the region."
Dr Smith, the Speaker of the House, will stand on National's party list at the November election and former policeman and security consultant Mr Mitchell has been chosen - after a contentious selection process - to stand in Rodney in his place.
Labour leader Phil Goff yesterday said he was encouraged by Mr Craig's news.
"We've got a very good candidate up there, Christine Rose ... If Colin Craig splits the vote, that assists her position and if he wins the party vote for his Conservative Party most likely he would take that from National.
"I don't know what sort of appeal he would have, he's certainly got a lot of money that he'll spend on his campaign and, given the splits and division and the unhappiness within the National Party there, it's possible that he could do more damage to the National vote than might otherwise be the case."
But Mr Craig believed Labour had little chance, even with his candidacy likely to split the centre right vote.
Polling conducted for the Conservative Party by Research First put Ms Rose's support at 9.9 per cent. That polling also put support for Mr Craig at 47 per cent against 36.3 per cent for Mr Mitchell.
"It's good but for those who do the homework and look back on how well I polled during the mayoralty ... I don't think it's too big a surprise."
Mr Craig's father, Ross Craig, a Rodney District councillor until the council was replaced by the Auckland Super City, said his son understood the area's issues and had the right to fix them.
"It's great to be back on the campaign trial, this time helping my son."
New Zealand First yesterday named Tracey Martin as its Rodney candidate.