David Shearer will put his leadership on the line as early as tomorrow, effectively putting rival David Cunliffe on notice to either "put up or shut up".
After a tumultuous annual conference that left the Labour leader exposed to months of speculation about his future, his inner circle yesterday signalled a vote was imminent to flush out Mr Cunliffe.
The crisis was sparked when delegates in Auckland on Saturday opted for a new constitution that would spark a run-off in February if just 14 of Labour's 34 MPs refused to back the current leader.
A block vote by affiliated unions effectively carried the day, with the key constitutional change passing by 264 to 237.
Instead of waiting, Mr Shearer's camp yesterday signalled the vote would be fast-tracked to tomorrow or at next week's caucus at the latest.
It seems certain the vote will be taken under the new rules, to keep faith with the party's wishes, but the Shearer camp was confident of victory last night.
"We have 23 solid for Shearer," an MP doing the numbers said.
Mr Shearer's hand seems to have been strengthened by a strong speech wrapping up the conference, where he announced a bold plan to build 100,000 affordable houses over 10 years.
Some wavering MPs also indicated they were put off by Mr Cunliffe over-playing his hand by refusing to rule out a challenge in February.
David Cunliffe got 10 votes from current caucus members last December, including his own. He also had the support of Carmel Sepuloni, but she of course is no longer there. Can Cunliffe's bagmen persuade another four MP's to cross over to the dark side.
The phones will be working overtime in the next 24 hours. Good on David Shearer for calling his rival's bluff.