The South Australian opposition will introduce a flat 50-cent fare across the metropolitan public transport network if it wins government at the March 2026 state election.

The policy, which the Liberals said would cost taxpayers $240 million over four years, would also extend to bus services in regional areas.

It is one of the party’s most significant election pledges to date, announced exactly six months out from polling day.

But the Labor government has slammed the plan, which Premier Peter Malinauskas said was “underfunded to the tune of $75 million dollars”.

SA Premier Peter Malinauskas poses for a series of portraits. He is wearing a dark jacket with red tie.

SA Premier Peter Malinauskas says the Liberal party have not properly considered the policy. (ABC News: Che Chorley, CHE CHORLEY)

Making the announcement on Sunday, Opposition Leader Vincent Tarzia said the policy offered relief for families struggling with the cost of living.

He said, under the scheme, a family of two parents and two students would save up to $100 a week for daily travel.

“This is an action that will make a genuine, practical difference to people working hard to get ahead,” he said.

Mr Tarzia acknowledged the idea is “not new”.

The former Queensland Labor government launched 50 cent fares as a six-month trial before the state election last year, and the policy was kept by the Liberals after they won government.

A train arrives at the platform of a heritage station

The policy would see fares dropped to 50 cents per passenger for all metropolitan public transport and all regional bus services. (Supplied: Department for Infrastructure and Transport)

“What we have done is tailored it in an appropriate manner to best suit South Australians,” Mr Tarzia said.

Opposition transport spokesperson Ben Hood said evidence from interstate suggested a flat fee boosted patronage by “up to 40 per cent”, which he said would be welcome in South Australia “where patronage is down significantly on pre-Covid levels”.

Mr Malinauskas said the government had “done the analysis” on the policy, and the Liberal costings fell well short.

“One of the reasons why it’s underfunded is because they’re not going to invest … in the additional buses, the trains and the trams that would actually be required to accommodate additional passengers,” he said.Adelaide buses on King William Street

Students can currently purchase a 28-day public transport fare for $10. (ABC News: Malcolm Sutton)

“You can’t talk about additional passengers coming onto the system unless you’ve got the trains and the trams and the buses to carry people.”

He pointed out that the Liberal policy would increase the cost of travel for students, after the government this year reduced the cost of a 28-day student pass to $10 — which equates to 25 cents per ride for travel to and from school.

Greens MLC Robert Simms backed the Liberals’ announcement, adding “it’s one the community supports”.