The average household would save thousands of dollars a year under a Greens idea for a government-owned supermarket chain.

Greens-affiliated think tank the Green Institute wants the federal government to buy 200 Coles and Woolworths stores and open more than 400 extra shop-fronts.

The idea has the back of the party’s new leader, David Shoebridge.

According to the Green Institute’s report, the average four-person household would save $60 a week, or $3134 a year, with the price of eggs, milk, fruit, vegetables, meat and cheese slashed by about a third.

The plan would cost $25.1 billion over five years, making it one of the top 10 most expensive government programs – more expensive than the Pharmaceutical Benefits Scheme.

“For half the cost of a single AUKUS submarine we could establish a national network of publicly owned supermarkets that would save families thousands of dollars on their groceries,” former Greens MP Max Chandler-Mather, who is the institute’s executive director, said on Tuesday.

“It’s common sense that if you want more affordable prices on essentials then you need to cut out the profit with public ownership.”

After the hefty initial bill, the stores would be self-funded, according to the report.

It’s a carbon copy of a policy spearheaded by wildly popular New York City mayor Zohran Mamdani. He is piloting five city-owned grocery stores across the Big Apple with the same objective.

It’s the second time the Greens have ripped a page out of Mamdani’s playbook. The party’s Victorian arm has already proposed creating a community safety and crime prevention office combining outreach, mental health, addiction and homelessness services with policing.

More than four-fifths of Australian voters, including a majority of One Nation supporters, somewhat or strongly support the idea of rolling out state supermarkets to cut the price of groceries, according to YouGov polling commissioned alongside the Green Institute report.

However, just 37 per cent of voters were in the “strongly support” column and those canvassed were not given details about the policy’s costings.

Shoebridge, the NSW senator who took over as Greens leader last week, has said the policy merits discussion.

He is under pressure to turn around the party’s languishing popularity as One Nation surges on right and progressive movements gain traction overseas.

While populist left leaders like Mamdani and Britain’s Zack Polanski make good headway in the polls, the Greens have barely moved from the 12 per cent vote share they scraped together at the 2025 federal election.

Chandler-Mather lost his Brisbane seat in that election, along with two of his lower-house colleagues, including the party’s then-leader Adam Bandt.

-AAP