David Cunliffe says he will support Labour leader David Shearer in any immediate caucus vote - but he will not rule out challenging for the leadership in February.
Mr Cunliffe told Morning Report he called David Shearer last night, leaving a message that he had his "absolute support".
However he could not pledge he would support Mr Shearer in February, when the leader faces a formal confidence vote.
"It may very well be that I'm in a position to reconfirm my support then but I'll make that final decision in February," Mr Cunliffe said.
He has left a February challenge on the table after Mr Shearer earlier said he would settle rumblings of a leadership spill "sooner rather than later".
"Leave it with me, we can talk about it next week and we can go over it then," Mr Shearer told TV3's Firstline this morning.
Mr Shearer said he never spoke with Mr Cunliffe except to exchange pleasantries at the weekend's Labour Party conference, where the topic of leadership was the dominant issue.
Mr Cunliffe denied this morning that he was playing games and said he had not derailed the conference by refusing to declare his support for Mr Shearer at any future vote.
"Mr Shearer does have my support. That's good for now, that's good for if there is a caucus vote any time soon," Mr Cunliffe said.
"I don't see any need to bring anything forward but if Mr Shearer wishes to do that he will have my vote."
Mr Cunliffe, who lost out to Mr Shearer in a vote for the leadership last year, complimented the leader's speech at the conference, where Shearer announced a $1.5 billion policy to build 100,000 basic homes for first home buyers.
"I thought it was a fantastic speech and I really agree with the policy," Mr Cunliffe said.
"David has my support and I have given him that support."
Mr Shearer said today that he would lead Labour to victory at the 2014 election, but he would not comment on how he would settle the leadership challenge.
"I'm not going to say what I'm going to do. What I will say that I will do is it will be my decisions going forward," Mr Shearer told Firstline.
"It will be the way I want it set out, it will be me making those decisions. I'm the leader, it will be my timetable and when we do that it will be behind us once and for all."
Mr Shearer described the leadership rumblings as one of the "issues" raised at the Labour conference that "need to be put to bed".
"And that's what I'm going to do in the coming days ... and they won't resurrect themselves again," Mr Shearer said.
"What happens this week will be me deciding that, and I can tell you right now I will be here in 2014 talking to you about what Labour's going to be doing in government."
Like Mr Cunliffe, Mr Shearer wanted to move the focus towards the housing policy announced at the conference.
"The bottom line is there have been issues come up as a part of the conference ... they've been magnified but they need to be put to bed. That's what I'm going to do."
Speculation about a challenge by Mr Cunliffe picked up steam after the conference passed changes to the party's leadership election rules, including allowing 40 per cent of the caucus to trigger a leadership contest.
He did little to quiet talk of a leadership challenge over weekend, refusing to endorse Mr Shearer or rule out a challenge, saying he had not made any decision.
With Mr Cunliffe refusing to pledge his support for Mr Shearer in February, there will be speculation he is waiting for the vote next year when the new election rules take effect.
Mr Cunliffe told Morning Report he had spoken to others in the party about the changes to the leadership election rules, which are seen to benefit a potential challenge from Cunliffe.
"I had my views, I expressed them as many others did."
Listen to David Cunliffe talk on Radio New Zealand's Morning Report:
Read more: Shearer will call on caucus
- APNZ with nzherald.co.nz