Light rail will be part of Auckland's future under a Labour-led government but it is too soon to say what it will look like, Prime Minister Chris Hipkins says.
Hipkins has also expressed his frustration over the progress of various projects that make up the Let's Get Wellington Moving banner.
National has promised to dump both Let's Get Wellington Moving and Auckland's light rail project if it is elected later this year.
Instead it is proposing a rapid transit network with public transport corridors in the North West (at a cost of $2.9 billion), Airport to Botany ($2.1b), and completion of the Eastern Busway ($717 million).
Hipkins told Morning Report a process has begun to determine the best options for light rail in Auckland.
But he would not commit to a specific route or whether the line will be surface or underground.
"We funded the business case so that that work can be done, and once that's done then we'll be able to give more detail but I'm not going to pre-emptively go ahead, otherwise, there'd be no point in doing that work."
A city the size of Auckland needed mass rapid transit but there were still questions to be answered on which option would be best.
In its transport policy announcement on Monday, National also promised to get rid of Let's Get Wellington Moving.
When asked about his attitude to it, Hipkins said it was "simplistic" to consider Let's Get Wellington Moving as a single entity. It was a series of projects ranging from some new roundabouts to major projects such as a possible new Mt Victoria tunnel and what to do around the Basin Reserve.
He pointed out the last National government had set up Let's Get Wellington Moving in a bid to resolve an impasse over upgrade plans around the Basin Reserve.
"Now for the last six years it hasn't delivered the sort of progress on Wellington transport projects that I think Wellingtonians would expect so what I've indicated is I think we need to have a good look on whether that's the right way forward."
The route from Ngauranga to the airport had been a bottleneck for decades.
"Successive governments have attempted to do things, they haven't succeeded. Ultimately we do need to make progress though ... Let's Get Wellington Moving doesn't seem to have been able to generate it (momentum)."
National was being disingenuous at the way it had gone about costing its $24b transport policy. In some instances it had obtained figures that dated from when it was last in government, Hipkins said.
He accused National of already backtracking on some costings, for example, the four-lane highway from Whangārei to Tauranga was initially priced at $6b in total. In reality, it would cost "a magnitude" more than that and National was now saying it did not mean the $6b figure it had quoted on its initial announcement.
"I think they probably need to spend a bit more time getting the details sorted," Hipkins said.
He cited other examples where National had underestimated costs, such as the Warkworth-Wellsford roading project which National said would cost $2.2b whereas Waka Kotahi estimated it would cost $3.5b to $4b.
"This is information they could have gotten hold of. They've chosen to use costings dating back in some cases to when they were last in government. Costs have gone up massively since then."
The government would soon release its policy statement on transport which would set out spending over the next three years.
Labour's transport policy which would take a longer term view on transport priorities would also be announced in the next few weeks. It was important constitutionally that there was separation between the two, Hipkins said.
On the the recommendation from an arbitration panel that teachers receive a 14.5 percent pay deal Hipkins said it came with "a significant price tag".
The government would need to look closely at the education budget to see how it could be paid for during a time when funding was under pressure.
Arbitration was entered into "in good faith" and the government would certainly consider the recommendations, Hipkins said.