WOOLWORTHS has bid farewell to single-use plastic bags under a new ban across the retail giant's stores.

From today, shoppers must bring along re-usable bags or buy them at the retailer's supermarkets, BWS, Metro and petrol outlets.

"This is a landmark day for us, not just as a business, but for our customers and communities, to help support a greener future for Australia," chief executive Brad Banducci said on Wednesday.

"We are proud to say that from now on, single-use plastic bags are gone from our stores, for good."

Mr Banducci acknowledged it could take shoppers a while to adjust to the ban.

"Putting 'reusable bags' at the top of your shopping list, keeping a couple in the car or leaving a post-it note on the fridge are some simple tricks that could work as a reminder," he said.

Woolworths and Coles last July joined a push to rid Australia of disposable plastic bags and set a deadline of June 30, 2018 for their stores to stop offering them to shoppers.

Woolies, which has provided more than 3.2 billion plastic bags a year to shoppers, later brought forward that deadline to June 20.

Green groups have welcomed the bans being introduced by Coles and Woolworths.

Similar bans in Britain and Ireland have helped reduce plastic bag usage by up to 85 per cent.

Woolworths and Coles have also recently announced plans to slash the amount of plastic wrapping on fresh fruit and vegetables in response to demand from shoppers.