It’s back to school for motorists.

After a holiday reprieve, petrol prices have leapt up to 20 per cent in the past week off the back of a spike in global oil prices and weaker Australian dollar.

According to the Motormouth website, the average price for standard unleaded in Sydney on Tuesday was sitting at just over 136 cents per litre, up from 113 cents a week ago.

Other cities including Brisbane and Melbourne have begun to come off after hitting the top of their cycle last week, but prices are still hovering at around 130 cents per litre across most of the country.

“It was always going to go up,” NRMA spokesman Peter Khoury said.

“We hit the low point of the cycle just after Christmas and New Year and it actually stayed quite low for longer than we thought, which was great. At one point the average price went below the wholesale price, which is rare but welcome.”

Mr Khoury said most areas were now at the high point of the petrol price cycle, so motorists should “definitely wait” to fill up if they could.

“Hold out, 100 per cent,” he said. “It’ll come back down again.”

He added that despite talk of further production cuts by the OPEC global oil cartel pushing up prices, he wasn’t expecting a return to the record highs seen in November last year which sparked nationwide protests

“We’re watching closely to see what impact it’s going to have,” he said.

The Australian Competition and Consumer Commission (ACCC) tracks the fuel price cycle in every city, and a number of consumer apps are available to find the best deal near you, including the NRMA’s MyNRMA and RACWA’s RAC Go apps.

In NSW, Western Australia and Northern Territory, retailers are required by law to report real-time price data, which is fed into the FuelCheck, FuelWatch and MyFuelNT services. The Motormouth app uses national data supplied by industry body Informed Sources, while the GasBuddy app relies on crowdsourced data