The ban on single-use plastic shopping bags, which takes effect on Monday, is "a step towards healthier oceans and giving nature a hand," Associate Environment Minister Eugenie Sage said on Sunday.

"New Zealanders are proud of our country's clean, green reputation and want to help ensure we live up to it. Ending the use of single-use plastic shopping bags helps do that," Sage said in a statement.

"From tomorrow, 1 July, the ban will cover all retailers," she said, adding new regulations mean local businesses can no longer provide their customers with a single-use plastic shopping bag to carry their purchases.

"The ban should ensure less plastic ends up in rivers, streams, stormwater systems and the ocean so seabirds, fish, turtles, and marine mammals are less vulnerable to being harmed by it," Sage said.

"At the start of plastic-free July, the plastic shopping bag ban is one step to tackling New Zealand's waste issues," she said, adding the government also needs to recharge materials recovery and recycling systems and shift to a circular economy.

New Zealand's mainstream supermarkets have already made the change away from single-use plastic shopping bags and report that this has stopped tens of millions of bags being handed out.

New Zealanders appear to have made a rapid transition to reusable bags, with 56 percent of shoppers in April 2018 bringing reusable bags increasing to 91 percent always, or often, bringing their own reusable bag in September 2018, according to a survey research done for the Ministry for the Environment.

"Lightweight single-use plastic shopping bags pollute nature because they are easily transported by wind and water. The phase-out encourages people to act with nature in mind," Sage said.

Businesses were given six months ahead of the ban to phase-out single-use plastic bags. There is an online portal on the ministry's website so people can report businesses that are still giving out single-use plastic bags after the ban takes effect.