Queensland’s Premier Steven Miles has promised to build not-for-profit petrol stations and trial a cap on bowser prices as Labor seeks a fourth term in office.

But experts questioned whether public petrol stations would have any meaningful impact on prices.

Miles unveiled an election pledge to lower petrol costs for motorists on Tuesday, saying a dozen public petrol stations will boost competition and help curb price gouging by “big multinationals”.

“I will legislate to limit petrol price rises to once per day and will require online notifications of any price rise the day before it happens,” Miles said in a speech to the CEDA on Tuesday afternoon.

“There is no need for fuel prices to be jumping around all day … I will give more power to consumers to get the best price.”

Motorist anger

The move is a response to motorist anger at high and unstable petrol prices in Queensland, with bowsers moving between an average of $1.97 a litre and $2.17 a litre over the past week alone.

The fluctuations – evident up and down the eastern coast – are caused by a cycle of multinational oil chains hiking prices before being undercut by independents, ACCC analysis has shown.

Geoff Trotter, founder of price comparison firm Fueltrac and a long-standing critic of the role oil giants play in setting petrol prices, welcomed the plan to cap prices as a win for motorists.

But he said building 12 publicly-owned petrol stations is unlikely to make much of a difference.

“One price change per day capped at 5 cents per litre should do away with the petrol price lottery,” Trotter said.

Macquarie University senior lecturer Lurion De Mello said the price cap proposal echoes a system in Western Australia, where the market for petrol has been regulated for decades.

“Western Australia provides pretty decent price stability,” De Mello said.

“It drives true competition because you know that if by 2.30pm you’ve not locked in a competitive price … you’re going to get priced out of the market.”

Public petrol stations

Miles’ wants taxpayers to fund the construction of 12 public petrol stations if Labor is re-elected.

They will operate on a cost recovery basis, meaning they won’t be established to make profits.

Energy Queensland will own the petrol stations, which will offer unleaded, diesel and electric vehicle fast charging.

The sites will be selected by experts to maximise their competitive impact, Miles explained.

“Public ownership can increase competition and keep petrol and diesel prices down,” he said.

But Trotter is sceptical that public servos will lower prices for motorists if Labor is re-elected.

“I don’t support government-run servos,” he said.

“There is no shortage of service stations [in Queensland] and 12 would make no difference to any pricing in south-east Queensland.

“It’s the manipulation of petrol prices that’s the issue, as evidenced by the fake fuel cycles.”

De Mello said other states would be unlikely to replicate the proposed public servo model.

“I don’t think 10 or 12 petrol stations will make a huge difference,” he said.

“The legislation has to come from the federal government, giving the ACCC some powers to control these [price] fluctuations across the board.”

Petrol prices capping

More consequential for motorists could be the plan to trial a cap on petrol prices and require servos to be more transparent about price changes, mirroring a model in WA.

Under the plan petrol stations would only be allowed to increase prices once per day, up to 5 cents per litre, and would need to notify the public online at least a day in advance.

In practice it would mean prices would increase by much smaller amounts at more regular, predictable intervals, as is currently the case in WA where the petrol market is regulated.

De Mello said Queensland regulating its market could have broader implications for other states such as Victoria and New South Wales, which have interconnected retail markets on the east coast.