Parliament erupted in laughter after Prime Minister Jacinda Ardern made a dig at Judith Collins' ambitions for National Party leadership in their first head-to-head clash as party leaders.
Collins took aim at the Government's failure to form consensus on Labour's election promise of delivering light rail from Auckland CBD to the airport, after New Zealand First raised concerns about ballooning costs.
The Prime Minister shot back by making fun of Collins' multiple attempts at the National Party leadership - a position she finally won last week following former leader Todd Muller's sudden resignation.
"I know the member is probably going to reference light rail to the airport," Ardern said. "I would say to the member that as she will well know, sometimes it takes a little longer than you'd like to get what you want."
The House erupted in laughter and applause.
Ardern said Cabinet gave "full consideration" to the two commercial proposals for light rail but neither option could be agreed upon by Cabinet - Labour and Greens were in favour but not New Zealand First.
"That project has now gone back to the Ministry of Transport to then be presented to those parties who have the privilege of forming Government," Ardern said.
The Government allocated $1.8 billion to light rail, but Ardern said the full cost of it would depend on the commercial arrangements for it, and that was not something Cabinet could settle on, so it was abandoned until after the election.
"I am still incredibly proud of the number of projects this Government has delivered and I see that the member has now delivered her own strategy for transport."
Ardern blasted the National Party's transport plan to use about $7 billion from the Government's $50 billion COVID-19 fund, and allow the New Zealand Transport Agency (NZTA) to borrow more, as well as cancel the Auckland regional fuel tax.
"I would point out the difference for this Government and National Party is that we have fully funded our projects. On the other side, the National Party are planning to raid the COVID Recovery Response Fund to the tune of $7 billion."
Collins continued taking aim at the Government's failure to get light rail off the ground, highlighting how Ardern in August 2017 said, "I am committed to starting straight away."
Ardern said she never denied it was a priority for the Labour Party.
"We formed a Government later on that year that was made up of three parties - not just one. That is the explanation for what happened with that project," Ardern said.
"I don't know what that member's explanation is for the fact that her Government announced projects that they didn't even start, and they didn't have a three-way coalition as an excuse."
Collins asked Ardern if she stood by her statement in July last year, when she was asked whether light rail was definitely going ahead, and said at the time, "Oh yes, yes, yes, absolutely."
Ardern argued that Labour remained committed to the project at the time and in "good faith" continued to assess the benefits of the project to Aucklanders - but she said ultimately consensus could not be reached.
The National Party's transport policy involves proposals to connect Auckland CBD to the airport. But National would scrap the light rail idea and instead expand heavy rail from the airport to Puhinui and Onehunga.