Single-use plastic shopping bags will be banned in Western Australia from July, bringing the state into line with other jurisdictions.
Premier Mark McGowan said on Tuesday plastic was "the curse of the earth" that killed wildlife.
"We want to make sure marine life, our wildlife, our very special environment is protected," he told reporters.
The state-wide ban will bring WA into line with South Australia, Tasmania, the Northern Territory and ACT, while Queensland will introduce a ban next year.
Coles, Woolworths and IGA have indicated they will ban single-use plastic bags, while some WA retailers already have.
But Environment Minister Stephen Dawson has ruled out supporting the WA Greens' push for balloons and plastic drinking straws to also go, saying he doesn't want to make parents' lives harder.
"As a father of a young child, can I say I'm not going to be a party pooper," he said.
Mr Dawson said he was confident the plan would pass the Upper House.
With the City of Fremantle having pushed for a plastic bag ban for more than five years, Mayor Brad Pettitt welcomed the announcement.
"Twice we have introduced a local law to ban businesses from providing single-use, non-biodegradable plastic bags to customers and both times the measure was blocked in state parliament," he said.
The original local law was disallowed in the Legislative Council in 2013 and a revised law was disallowed in 2015.
In April, the council adopted the plastic bag reduction local law for a third time.
Conservation Council of WA director Piers Verstegen said the move showed growing community and industry support to address plastic pollution.
"WA is one of the last states where single use plastic bags have not yet been banned and our environment and marine life is suffering," he said.
"Millions of plastic bags find their way into creeks, rivers, wetlands and the ocean every year in WA and this pollution has a huge impact on marine life and aquatic ecosystems."
