The Prime Minister's denying she's breaking pre-election promises over the fuel tax announcement.

The government's 10-year transport plan proposes a fuel tax increase of between nine and 12 cents per litre.

READ MORE: Motorway projects gone, fuel taxes up

Jacinda Ardern told Mike Hosking the increase can come in this term.

That's in spite of Labour earlier committing to not bringing in any new taxes in the first term in Government.

But Ms Ardern says it's an excise - not a new tax.

"Road excise charges have been in existence for forever and a day and whenever we put these documents out we routinely discuss what we are going to do with it, it is the same with what we do on tobacco excise, we consistently review where they sit."

LISTEN ABOVE AS JACINDA ARDERN SPEAKS WITH MIKE HOSKING