Judith Collins has defended not costing some of her party's big-spending transport plans, saying it would be "dopey".
In her first big policy announcement as National leader, Collins this week unveiled a $31 billion plan to get Auckland and the northern regions moving again.
Asked on Newshub Nation on Saturday if it was her 'think big' moment - a throwback to Sir Robert Muldoon's big projects of the late 1970s and early 1980s - Collins said it was more 'think smart'.
"Congestion would be the number one bugbear for Aucklanders and those in the northern regions. It's the number one issue in my electorate of Papakura, it's the number one issue in my colleagues' electorates around the Auckland region.
"I tell you, it's the one we've actually got to actually deal with and it's a big fat one and we're going to sort it."
But some of it - such as tunnels under the Brynderwyn and Kaimai mountain ranges - didn't come with precise costings attached.
"There are some big holes in today's announcement that need answers," Finance Minister Grant Robertson said on Friday.
Robertson sent a text to Newshub Nation saying even if the tunnels were geotechnically feasible, National hadn't attempted to put a cost figure on them.
"We haven't costed those out," said Collins. "They are a long-term plan and we wouldn't be starting to even do say, under the Harbour Bridge, for some time. They will be told... We're not planning to actually start them for eight or 10 years... The fact the Finance MInister's texting you about it this morning shows you how worried he is, doesn't it?"
The second Harbour Bridge wouldn't start construction for another eight years, Collins said, and rail to the airport until 2030.
"What we can't have is a Government coming in, stopping everything that's been started, messing up all the contractors' contracts, wasting time and money on things," said Collins.
"We're saying, this is where we see the country going - it would be great if the other parties came on board and said 'we share that vision'. I think a lot of New Zealanders are wanting to see long-term plans, visionary ideas... look, we're not going to try and cost something that might be done in 20 years' time. Trying to do it now? It's just dopey to do that. They know this - it will be invested and it will not be wasted."
It's unlikely the other parties will be happy to come on board. Labour said it already has a "fully funded infrastructure pipeline that will create jobs immediately in response to COVID-19".
"National's plan puts those projects and jobs at risk while piling billions more debt onto NZTA that will ultimately be paid for by taxpayers," said Robertson.
Associate Transport Minister Julie Anne Genter said it would be "hard to imagine a more irresponsible and climate change-denying proposal", calling the Onehunga busway plan "truly mystifying" as there "already a rail line and services to Onehunga from the CBD".
"Recipe for more bus congestion, traffic & pollution," she tweeted.
Collins also defended her support for new roads being paid for by tolls, denying it was a tax because driving on the new roads would be optional.
"It's a choice that you're making to pay something for that road. When I'm on these expressways where there's a tax... I pay a fee which I don't have to. I could instead waste more of my time travelling around the other road for free and using up my petrol - I'm taking a choice on that very small fee. I'm very happy to do that, as long as there is an alternative."
She also said any congestion tax in Auckland would be agreed on with Auckland Council and "revenue-neutral" so motorists wouldn't be punished.
"Whatever we do has to be revenue-neutral - it's got to be revenue-neutral otherwise it's just going to be an added cost to Aucklanders and New Zealanders who are currently already paying to sit in traffic while nothing seems to get done."