"We're phasing-out single-use plastic bags so we can better look after our environment and safeguard New Zealand's clean, green reputation," Ardern said.
"Every year in New Zealand we use hundreds of millions of single-use plastic bags – a mountain of bags, many of which end up polluting our precious coastal and marine environments and cause serious harm to all kinds of marine life, and all of this when there are viable alternatives for consumers and business."
Ardern said the Government had listened to the 65,000 New Zealanders who had this year called for the ban through a signed petition.
"It's great that many people are already changing the way they shop. But it's important we take the time now to get this right so we can help all New Zealanders adjust their shopping habits," she said.
"We need to be far smarter in the way we manage waste, and this is a good start."
During her address, the Prime Minister outlined the Government's commitment to tackle environmental challenges.
"Just like climate change, we're taking meaningful steps to reduce plastics pollution so we don't pass this problem to future generations."
First Retail Group managing director Chris Wilkinson said the move was positive.
"While the key players in the retail sector have been moving quickly and decisively to shift consumers away from plastic bags, many smaller retailers have not had the same appetite - often for fear consumers will respond negatively," Wilkinson said.
"The government-led approach will ensure everyone is on the same playing field, helping alleviate that concern."
Wilkinson said consumers had responded well to large retailers who had already stopped supplying or committed to stop supplying single-use plastic bags.
"Consumers are already responding well to the bigger retailers that have made the move from plastic and there's a general realisation now of the damage this packaging is doing.
"Some of the chains we work with are saying shoppers are almost apologetic if they use a plastic bag, so the message is getting through successfully."
New Zealand's largest retailer The Warehouse Group, which also operates Warehouse Stationery, Noel Leeming and Torpedo7, has today announced that it will now only offer reusable bags in its store, ahead of its plans to introduce compostable bags.
Bunnings has long been plastic bag-free and supermarkets giants Countdown, New World, Pak'nSave and hardware chain Mitre 10 have already committed to phase out the use.
In June, 13 companies marked World Environment Day by committing to using 100 per cent recyclable packaging by 2025.
Five trillion plastic bags are used worldwide every year. Photo / File
New Zealand-based Foodstuffs, Countdown, New Zealand Post and Frucor Suntory, and multinationals Amcor, Danone, L'Oreal, Mars, PepsiCo, Coca-Cola, Unilever and Nestle signed the NZ Plastic Packaging Declaration.
Countdown, Fresh Choice and SuperValue announced they would phase out plastic straws by October 1 this year and move towards 100 per cent reusable, recyclable or compostable packaging by at least 2025.
Greg Harford, general manager of public affairs at Retail NZ, said the organisation had been calling for Government leadership on the issue for some time.
"It is good news that the Government is stepping up to help retailers tackle the issue of reducing plastic waste," Harford said.
"Kiwis have demonstrated they are concerned about our marine environments and we have generally seen really positive outcomes from those retailers who have already eliminated plastic bags all together."
He said there had been confusion in the market about so-called 'biodegradable' and 'compostable bag' alternatives.
Today marks the beginning of the end for over 2 billion single-use plastic bags that clog our communities, coasts, rubbish dumps and oceans each year.
"Including these in the Government's proposal is a signal that they may not stack up, given that we do not yet have the proper infrastructure to process these kinds of bags effectively in New Zealand at any kind of scale."
In a statement, Greenpeace said it was celebrating the phase-out of plastic bags.
"This could be a major leap forward in turning the tide on ocean plastic pollution and an important first step in protecting marine life such as sea turtles and whales, from the growing plastic waste epidemic," Greenpeace oceans campaigner Emily Hunter said.
"Up to 12.7 million metric tonnes of plastic waste enters the ocean every year - that's the equivalent of one garbage truck every minute and single use plastic bags are just the tip of the iceberg.
"Today marks the beginning of the end for over 2 billion single-use plastic bags that clog our communities, coasts, rubbish dumps and oceans each year."
Associate environment minister Eugenie Sage said many countries and global cities including six states in Australia, Belgium, France and Italy had already banned single-use plastic bags and microbeads.
Around 12.7 million metric tonnes of plastic waste enters the ocean every year. Photo / 123RF
Forty-one other countries such as Ireland, Wales and South Africa had introduced levies to drive down the use of plastic bags.
In December Government introduced a ban on the sale and manufacture of plastic microbeads.
Sage said she believed New Zealanders would embrace the plastic bag ban.
"Public calls for action have encouraged a significant number of retailers, including supermarkets, to move on single-use plastic bags. We want to support their efforts by ensuring the retail industry moves together in a fair and effective way," Sage said.
"[We] will work alongside supermarkets and other retailers to help people make the change to reusable bags and we want to hear from New Zealanders as to how we can best do this."
