Held in their usual room in Parliament , it was spent farewelling MPs voted out, welcoming a new contingent, and voting for a new leader and deputy leader.
Leader Helen Clark and deputy Michael Cullen both stood down in the wake of the election defeat.
Going into the meeting Helen Clark said she had an incredible 15 years as leader, which had been a privilege.
"But I've made the right decision for the Labour Party and for myself, now I am looking forward to giving the new team my total and unconditional support," she told reporters.
Miss Clark said she had never had a Plan B and her plan now was to help with the transitional period before having some time off.
"Then I will just be looking to the next steps, working with the new team to support them and of course as MP in my electorate."
Asked if she was there for the full term Miss Clark said she would settle into her new job.
Dr Cullen said his departure as finance spokesman and deputy leader was inevitable.
"I've been the finance spokesperson for the labour party for 17 years, the minister of finance for nine years, deputy leader for 12-1/2, we've just lost an election which was not about issues but basically about simply changing the personnel."
Dr Cullen was light-hearted but had fighting talk for National.
"We've got the best and strongest intake we've had since 1984, it's a generation, the base for a very strong performance by us moving forward so our message is to the National Party, being a law and order party, is three years and you're out."
Asked if Dr Cullen was going to remain in opposition for the full three years he answered: "I'm not going to go into government, no, they haven't offered I'm afraid," Dr Cullen said.
But then he answered more seriously.
"I can't commit to that at this stage, I will be around for some time to come but I will make my own mind up about that somewhere down the track."
He saw a role in helping the new contingent.
"(They have) three years to learn the ropes, to learn how we are going, I hope to give some help in the Parliamentary side of that matter and then a strong position to be part of the sixth Labour government in 2011."
Dr Cullen expected less onerous responsibilities and did not rule out shadow leader of the House considering his 27 years experience.
Dr Cullen revealed to journalists he had been grumpy for a period because he had been having trouble sleeping.
He did not want to sit on the backbench to barrack.
"I am going to sit somewhat closer and still crack jokes...I don't want to become one of those old men in the Muppet Show up the back."
Going into Caucus Judith Tizard wore a black badge that said "bugger" and most MPs had to be shown the right room to go in, as a pre-Caucus lunch was being held in a nearby room.
The new list MPs are former race relations commissioner Rajen Prasad, 28-year-old policy adviser Jacinda Ardern, Auckland lawyer Raymond Huo, former Oxfam global head of policy Phil Twyford, 31-year-old part-Tongan part-Samoan primary school teacher Carmel Sepuloni, former prime minister Walter Nash's great grandson Stuart Nash, school principal Kelvin Davis and unionist Carol Beaumont.
New electorate MPs are Clare Curran in Dunedin South, Grant Robertson in Wellington Central, Chris Hipkins in Rimutaka, Iain Lees-Galloway in Palmerston North, and Brendon Burns in Christchurch Central.
New Zealand First also had its last Caucus after narrowly missing the 5 percent threshold.
Dail Jones was the only member to run the media gauntlet. He put on a brave face despite his party's defeat, simply repeating "no comment". When asked whether he understood the meaning of "NO", he laughed his way into the elevator.
In a statement leader Winston Peters said the party would regroup and return.
"No one in the caucus is walking away. There is too much at stake over the next three years for us to turn our backs on tens of thousands of supporters," he said.
