The meeting began at 9.45, starting with a farewell for outgoing MPs Brendon Burns and Raymond Huo before Phil Goff presents his final report as leader.
Mr Shearer's camp was reporting yesterday that it had the numbers to take the vote with a few to spare after the final flurry of lobbying to try to secure the undecided MPs.
Two of the 34 MPs - Maryan Street and Charles Chauvel - will have proxy votes because they are overseas.
The winner will need at least 18 votes and Mr Shearer's camp believed last night he had at least 20. However, he was wary about MPs changing their minds or going against their promises in the privacy of the secret ballot.
Mr Shearer said he was "quietly confident but it's still going to rely on the people on the day. You can never be absolutely sure".
Yesterday Mr Cunliffe continued to insist the numbers were even and the deciders would be a handful of about five MPs. He denied he was talking up his support to try to stop his own vote collapsing if his supporters sensed Mr Shearer would win.
"Our numbers are solid and this is going right down to the wire. I would be surprised if there was more than one vote in it."
While most MPs had made up their minds, both contestants were wooing undecided or soft votes yesterday, including Shane Jones.
The party's union affiliates have not taken a stance on their preferred leader. However, many members thought Mr Cunliffe performed better at the six roadshow meetings for the leadership contenders with members, which were closed to media.
Labour-aligned blog The Standard has backed Mr Cunliffe.
He said the support for himself and his running mate, Nanaia Mahuta, was encouraging.
"There is a growing recognition by the rank and file that we are ready now and that has strengthened over the week."
It is unclear how much that support reflects the views of the wider membership rather than some more vocal members.
One MP said after the final meeting in Auckland several party members sent emails, all of which were in favour of Mr Cunliffe. The MP's local organisation also favoured Mr Cunliffe following that meeting and that helped decide the MP's vote.
However, other MPs said they continued to be nervous about Mr Cunliffe's ability to put together a unified team - a concern he has struggled to dispel.
While Mr Cunliffe is understood to have promised some MPs positions in his lineup if he wins, Mr Shearer has refused, although it is now widely expected his deputy will be Grant Robertson.
Mr Shearer said he did not regret refusing to promise positions, although it would have made the vote gathering easier.
"If you offer people things it's very difficult to put a team together of both sides after the event. That makes it difficult to unify the caucus."
Mr Cunliffe has promised Mr Shearer a front-bench role if he wins the contest.
Mr Shearer has not promised the same, but said yesterday Mr Cunliffe was highly talented and he would want to make the most of that.
