Queensland Premier Steven Miles says Labor will establish 12 publicly owned fuel stations if re-elected in October, with the sites to be determined by where competition is most needed across the state.

Mr Miles said the state-owned fuel stations would operate on a cost recovery basis and would sell petrol and diesel, alongside electric vehicle fast chargers.

"Publicly owned fuel stations will charge a fair price for fuel, increase competition, and ensure Queenslanders have more choice when it comes to filling up," he said. 

In his State of the State address on Tuesday, Mr Miles also announced Labor's plan to ban petrol stations from raising the price of fuel more than once a day and a trial to cap price increases to 5 cents a litre a day. 

Australasian Convenience and Petroleum Marketers Association chief executive Mark McKenzie told ABC Radio Brisbane it was unclear if Labor had the ability to implement the plan.

"We'll adapt to where the government goes," he said.

"There's no legislative mechanism or precedent, not just here in Australia [but] anywhere in the world."

Asked how he would legislate the price cap, Mr Miles said similar measures had been implemented in other states, with Western Australia requiring 24 hours notice before the price is increased.

"It is all about trying to shorten the cycle to work out which day of the week you can fill up," he told ABC Radio Brisbane.

'We need to see more competition'

Mr Miles said he expected the 12 state-owned petrol stations would be opened in Brisbane and some regional areas, adding that he had been "convinced by the RACQ that we need to see more competition".

"We want to first support independents into the market, but where that fails or where that doesn't happen quickly enough, we are going to set up state-owned petrol stations."

Mr McKenzie described the plan as a "bold and risky move with Queensland taxpayer funds".

Shadow treasurer David Janetzki said he was concerned state-owned petrol stations would put small businesses at risk.

"The big corporates will win and ultimately independent operators and corner stores will fold," he told ABC Radio Brisbane.

Fuel price cycle not in 'best interest of motorists'

The RACQ reported for the March quarter of this year the retail margins on unleaded petrol in Brisbane were almost triple those charged in Perth.

RACQ General Manager of Advocacy Joshua Cooney said Brisbane was consistently the most expensive capital city in the country for fuel. 

"We have a fuel price cycle that doesn't work in the best interests of motorists," he told ABC Radio Brisbane. 

"For many years now motorists have faced eye-watering prices at the bowser with record high fuel margins and unjustified price hikes, so something has to give."