At a time when the party needs to start rebuilding urgently if it wants to appear credible to voters in 2014, MPs will be counting the numbers of supporters in a reduced caucus of 34.
The winner will have the difficult job of uniting the factions to give Labour some momentum in the House, given it will be up against an invigorated and enlarged Green caucus and New Zealand First leader Winston Peters and his team of new MPs.
Labour leader Phil Goff said yesterday he would not quit Parliament this term, but would not comment on his position as a future leader.
The decision would be his and would be in line with his previous comments that he would leave the leadership on his own terms.
Labour has five or six MPs lining up as potential leaders but only two with some credibility - David Shearer and Lianne Dalziel. However, it is thought Ms Dalziel will not see out the full term, resigning in about a year to 18 months to start campaigning to become the mayor of Christchurch.
She held her seat well on Saturday night against the National Party tide.
David Shearer also performed well in his electorate, Mt Albert, but contenders David Cunliffe and David Parker did not have the best of elections.
Mr Cunliffe increased his margin over National's Tim Groser but National won the party vote in New Lynn.
In Epsom, Mr Parker secured only 3093 electorate votes and brought in 4777 party votes.
Wellington Central MP and campaign spokesman Grant Robertson increased his personal majority by more than 3000 votes but National won the party vote by more than 4000 votes.
That result reflects the decision of the campaign team, led by Trevor Mallard, to not run a two-ticks for Labour campaign.
Instead, only the candidate's name and face appeared on hoardings.
Shane Jones appears to have ruled himself out of challenging for the leadership and would not say who he would support.
Mr Goff has some of the strongest credentials to remain as leader, if he chooses.
Yesterday he took full responsibility for Labour's campaign but the Otago Daily Times understands he was set up to fail and the behind-the-scenes jostling to replace him as leader distracted the Labour campaign.
Asked if he would serve a full term as MP for Mt Roskill, regardless of what happened with the leadership, Mr Goff said "absolutely".
"I have no plans to retire from Parliament. I was elected with a very strong majority to serve the people of Mt Roskill. I've served them for nearly three decades and I'm going to keep on serving them," he said from his Clevedon home.
Mr Goff said he took responsibility for Labour's result in the election, but he did not resile from the policies Labour put up, saying "brave" policies were critical for the future of New Zealand.
Deputy leader Annette King could be a caretaker leader until the dust settles from probably Labour's worst defeat at the ballot boxes.
Mr Goff said he would tell his caucus tomorrow of his decision. He had already told some MPs.
