NSW Premier Gladys Berejiklian says she does not need to ban plastic bags in NSW, "because 80 per cent of plastic bags" will already be banned by the supermarkets themselves.

Addressing a meeting at the Tweed Chamber of Commerce on Monday, Ms Berejiklian welcomed the recently announced plastic bag bans at Coles, Woolworths and Harris Farm Markets, but said they were the very reason she did not need to legislate a state-wide ban as Premier.

"[Coles, Woolworths and Harris Farm] produce about 80 per cent of the plastic bags in NSW, so in essence they themselves would ban the plastic bag," she said.



"I don't need to [put a ban in place] because 80 per cent of plastic bags are already banned. I don't need to put a law in for something that's already happening."



The comments have hindered hopes among environmental advocates, who considered the recent commitments from Australia's major supermarkets as a positive sign that there remained no more barriers to introducing a ban across NSW.

"Despite the action by Coles, Woolworths and Harris Farm, data shows that at least 10 million bags will continue to pollute the state's environment each year," said Jeff Angel, director of the Boomerang Alliance of 47 groups.



"The facts are, the retailers' actions are voluntary and not enforceable. Key business sectors have called for a level playing field; and the community wants a full ban.