The AA wants to see the business case for light rail to Auckland Airport and Westgate.

The Government plans to introduce a regional fuel tax to pay for light rail, as well as other infrastructure projects.

Auckland Councillors would first have to endorse the tax, then the Council would have to request it.

Automobile Association spokesman Barney Irvine says Aucklanders should have a say through consultation about the Long Term Plan early next year.

"In principle we have no problem with a regional tax for this project, especially the connection to the west, but our members would want to see the merits clearly laid out before they start paying 10c more per litre or whatever is proposed.

"We'd also need to see strong business cases for any projects that are going to be funded by any new tax like this and we certainly don't have that at the moment with the projects that've been proposed."

Irvine also wants reassurance that the tax will only be collected in Auckland, not averaged across the country.