Napier MP puts leadership aspirations on hold as former union boss weighs bid against Cunliffe and Robertson.
Napier MP Stuart Nash has ruled himself out of the Labour leadership contest so he can turn his electorate into a "Labour fortress".
Mr Nash had previously indicated his decision would be influenced by whether list MP Andrew Little was in a position to stand.
Mr Little's place in Parliament was confirmed on Saturday following the counting of special votes.
Last night, Mr Nash confirmed his withdrawal from the contest and said he had decided against standing after a meeting with his team yesterday. Mr Little's situation had had only a small bearing on his decision.
"We had a good look at everything and decided there's a whole lot of work to do in Napier ... to turn Napier into a Labour fortress."
Labour's final vote went up from 24.7 per cent to 25 per cent when specials were counted. That prompted Mr Little to confirm he was considering a tilt at the leadership.
Last night, the former union secretary said he would make his decision by the end of this week.
Mr Little said he was mindful of the fact he had barely held his place and had been defeated twice in the New Plymouth electorate.
"It's the symbolism, I think, more than anything that counts. Those are factors that weigh against putting myself forward. That is a big factor I've got to weigh up."
He said another crucial factor was whether he could gain the trust and confidence of caucus colleagues.
The prospect of Mr Little as leader was welcomed last night by at least one of those colleagues who believed he could unite the party's bickering factions more easily than either of the confirmed contenders, David Cunliffe and Grant Robertson.
"I'd probably still have an open mind about who I'd eventually back ... but I think he's a worthy contender," said the MP, who declined to be named. "He is someone who is seen as not being as factional as the other two candidates and might have the ability to pull the caucus together.
"I think he's got some appeal out in the broader public, although his name recognition probably still isn't that great."
The deadline for nominations is October 14.