Environment Minister Nick Smith has praised The Warehouse for trying to reduce the use of plastic bags and says he hopes other retailers will follow its example.

From April 20 customers will be charged 10 cents per bag at the checkout. The Warehouse hopes this will see 20 million bags taken out of circulation over the following 12 months.

"We expect the new charge will significantly reduce the unnecessary use of plastic bags," chief executive Ian Morrice said.

Dr Smith said more than a billion plastic bags were used in New Zealand each year and they added to excessive waste that ended up in landfills.

"The small charge will just make people think again as to whether they really need a plastic bag," he said.

"I commend The Warehouse for its initiative and for its environmental leadership."

Mr Morrice said a recent survey of 600 Warehouse customers showed 78 per cent supported the change, with 85 per cent of those affected by trials at stores saying they would choose not to use a plastic bag once the charge applied.

The cash collected from those not ready to let go of plastic bags will be donated to local community groups and the bags can be returned to The Warehouse stores for recycling.

The move has been on the cards since The Warehouse joined a number of major retailers in signing the Packaging Accord 2004 which set a goal of reducing the number of bags used by a fifth (144 million bags) by 2009.

By January 2009 some 100 million had been taken out of circulation as the campaign gained traction with shoppers. A survey by AC Neilson, released in January, found a third of New Zealanders owned a re-useable shopping bag.

Other signatories to the Accord include Foodstuffs New Zealand, Progressive Enterprises, Woolworths, Mitre 10 and Caltex.

Others such as Bunnings and Borders had their own schemes to cut the use of plastic bags.