There's backing for an initiative to get Kiwis to use fewer plastic bags.

Mayors in Auckland, Wellington and Dunedin are asking for the power to charge a 10 cent levy on each plastic bag, hoping to stop a billion of them ending up in landfills each year.

Environment consultant Matthew Luxon said it's a great initiative and says similar measures have proved effective in South Australia and the UK.

"...I think there's no reason it couldn't work here in New Zealand," Mr Luxon said.

"What it does is that it encourages people to reuse."

He believes the levy could reduce bag use by 80 percent.

"You could do it in the first hundred days of a new Government - it's not a hard thing to do, so why wouldn't you?" Mr Luxon asks.