Key Points:

New roads around Auckland might be paid for by tolls on drivers who use them if National wins the election.

The party's transport spokesman, Maurice Williamson, said yesterday that commuters could face bills of up to $50 a week for tolls of $3 to $5 a trip on new motorways or similar "roads of national importance".

But he believed that most people, if given a choice between tolls or queuing on free roads, would gladly pay.

"If that was translated into a lot less money than you're currently burning just sitting going nowhere, most New Zealanders will go with it," he told the Herald.

Mr Williamson said National had yet to decide which new roads might be built from extra loans of up to $750 million a year, possibly to be repaid from tolls, but he listed several possibilities in and around Auckland.

Transit NZ - now part of the Transport Agency - backed off imposing tolls on the Auckland ring route because of public opposition, but Mr Williamson said that was because it did not ask the right questions.

"If you go out to the public and say, 'Would you like to pay more?' no one is going to say yes to that," he said.

"You have to consult with the right questions, saying [tolls] will mean major reductions in fuel and time."

He believed an obstacle to public acceptance of tolls had been removed by a new law requiring all money raised from fuel taxes to be paid into the national land transport fund.

"I think New Zealanders will now say, 'Well okay, if it is going to provide a solution to a problem I face and you are not stealing my petrol tax, well then I'll go for it'."

Mr Williamson promised more law changes to make it easier to attract investment for public-private partnerships (PPPs) for projects such as the Waterview tunnels on the western ring route.

He said although such partnerships between the Government and private firms had been possible since 2003, the fact there were still no PPP transport projects highlighted obstacles such as the 35-year limit on charges imposed to recover costs and make a profit.

"Other countries have more realistic timeframes, in the order of 50 and 60 years, to get a reasonable return on your investment."

But Mr Williamson acknowledged that being slow to start with PPPs gave New Zealand the advantage of learning from mistakes made elsewhere, such as in Australia, where the state initially allowed private investors to take "all the windfall gains" and let losses be paid for from the public purse.

Asked about a statement he made on Television One's Agenda programme that tolls would be imposed only on new roads, he said exceptions might be needed for projects such as another Waitemata Harbour crossing.

Charging tolls on a tunnel under the harbour while keeping the harbour bridge toll-free would lead to a "dreadful distortion" in traffic, against which he believed even Labour would make an exception.

Transport Minister Annette King accused Mr Williamson of not thinking his toll plans through properly.

She said that even if the $365 million Albany-to-Puhoi toll road, to open early next year, had "maximised" use, a $2 toll would still pay only half its cost.

"Maurice Williamson misses out on the fact that you need to have a balance - that you cannot set a toll so high that people won't use the road," Ms King said.

But she said the Labour-led Government believed strongly there was a place for PPPs.

Mr Williamson listed these possible candidates for tolls:

Auckland's next crossing of the Waitemata Harbour (expected to cost at least $4 billion).

Auckland's motorway tunnels through Waterview on the western ring route ($1.9 billion).

A 19km motorway extension to Warkworth or beyond ($1 billion-plus).

Completion of the Waikato Expressway on State Highway 1 ($1 billion).

Kopu Bridge, on the way to Coromandel Peninsula ($32 million).