Unleaded petrol across metropolitan Adelaide soared to an average $2.15 a litre as service stations hiked prices, with the RAA warning the high cost was likely to remain in place over the week.

RAA spokesman Mark Borlace said motorists were able to fill tanks for around $1.70 a litre for unleaded petrol yesterday, before service stations pushed up prices to well over the $2 a litre mark this morning.

Borlace said that the last time prices were this high was in July last year, when they peaked in a 14-year high at between $2.50 and $2.60 a litre after the Russia and Ukraine war saw about 10 per cent of oil cut off from the world market.

This led to a temporary halving of the fuel tax by the former federal Morrison government to help Australians with cost of living prices.

Borlace said the global deficit in oil had been returned to the market through other sources and today’s price spike was driven by marketing from fuel companies in the typical fortnightly cycle of pricing across Adelaide and stretching to Mount Barker.

“The cycle usually is about a fortnight so if you can make a tank of juice last a certain time – it takes about two weeks to taper back to a lower price and you can fill up for a lower price again,” he said.

Country regions were not as affected by the price cycle, with not as much competition among service stations.

That means it’s currently cheaper to fill up outside Adelaide, with prices in regional areas fluctuating from $1.99 a litre for unleaded petrol in Port Augusta to $1.92 in Berri.

Borlace said that in Adelaide it was the “smaller independents that are cheaper and the most aggressive in their pricing”.

Borlace said the RAA real-time fuel price map online and a real-time RAA app funded in last year’s State Budget meant those struggling with the rising cost of living across the state could shop around for cheaper fuel prices.

He also said that there are typically three types of car drivers when it comes to fuel purchasing habits.

“One, you are rich enough to say ‘I don’t care, I’ll fill up where I usually fill up’, two, some people have their fuel paid for by their employer or company, and then there’s the rest of us who want to save $24 in filling up on the best day,” he said.

Some service stations keep prices lower to draw in more motorists and to make their margins on food, drinks or car washes.

After the RAA advocated for years for South Australians to have ready access to the cheapest fuel, the State Government committed $1.8 million to extend the mandatory Fuel Price Transparency Scheme in last year’s budget.