David Cunliffe's hopes of securing the Labour leadership rest on the party's six Maori MPs and newcomers to Parliament.
A count of where MPs are leaning shows Mr Cunliffe's rival, David Shearer, is a whisker away from securing the 18 votes required to win. But some MPs indicated their minds could change.
Yesterday's announcement that Grant Robertson would run as deputy leader and was supporting Mr Shearer could also shuffle the numbers.
Sources from Mr Cunliffe's team last night said the contest was close, with only a few MPs still undecided.
His chances rely on securing the support of the six-strong Maori caucus and some of the new MPs.
His team has two Maori on it - running mate Nanaia Mahuta and Moana Mackey - and is relying on other Maori MPs backing Ms Mahuta.
Mr Cunliffe has also indicated Shane Jones would get a high position, possibly finance spokesman.
Yesterday caucus kaumatua Parekura Horomia said he would back Ms Mahuta's bid for deputy, but "not necessarily" with Mr Cunliffe as leader. Ms Mahuta has ruled out acting as deputy other than for Mr Cunliffe.
The four leadership contenders were in Hamilton last night for the first of six meetings as part of a national tour to speak to party members.
Mr Shearer has ruled out running on a ticket, saying it was up to caucus to choose a deputy. Yesterday he said he would welcome Mr Robertson as his deputy, if chosen.
Mr Robertson said although Mr Shearer was refusing to put up a formal ticket, "I'm certainly supportive of him and when you talk to him, you'll find he's supportive of me."
Mr Robertson said the pair had "complementary talents" and he had significant political experience from his work as an adviser to former Prime Minister Helen Clark and a diplomat at the United Nations in New York.
Labour president Moira Coatsworth has begun work for a party review after its dire election result, seeking members' views. The national council will meet on Saturday.
Where the MPs are likely to vote
Labour's 34 MPs will select the leader by secret ballot on December 13.
Grant Robertson (deputy), David Parker, Annette King, Maryan Street, Damien O'Connor, Phil Goff, Phil Twyford, Kris Faafoi, Darien Fenton, Clayton Cosgrove, Trevor Mallard, Jacinda Ardern, Chris Hipkins.
Nanaia Mahuta (deputy), Moana Mackey, Charles Chauvel, Lianne Dalziel, Brendon Burns (if wins Christchurch Central), Parekura Horomia, Louisa Wall, Rino Tirikatene.
Clare Curran, David Clark, Iain Lees-Galloway, Shane Jones, Su'a William Sio, Andrew Little, Rajen Prasad, Sue Moroney, Ross Robertson, Ruth Dyson, Megan Woods, Raymond Huo (depending on Chch Central result).