Labour transport spokesperson Michael Wood says "sources suggest" that National is considering a fuel tax to fund its roads of national significance (RONS) project.

But a spokesperson for National says that's not true, as the fallout over finance between the two parties continues.

Mr Wood said "While the Government keeps up its stream of lies about Labour's tax policy, sources indicate that the Ministry of Transport has been conducting secret modelling work on a 5-10 cent nationwide fuel tax increase to fund National's $10.5 billion RONS programme."

Mr Wood says this would be on top of the 15 cent per litre increase on fuel tax that National has already implemented to fund a previous RONS project.

A spokesperson for National told Newshub that they're not planning a fuel tax.

"No. Labour is the party that wants to increase taxes on hard-working New Zealanders, not National. Mr Wood needs to go familiarise himself with Labour's tax manifesto," they said.

If Labour is elected to government, they would give Auckland Council the ability to implement a regional fuel tax. The party expects this will generate $150 million a year for Auckland transport.

Newshub.