PETROL prices have hit a four-year high, with motorists urged to shop around for the best deal.

The cost of unleaded petrol jumped 5.1 per cent to an average 142.5 cents a litre in most capital cities during the past three months, a survey by comparison website comparethemarket.com.au found.

The increase pushes prices to their highest level since mid-2014, with some drivers paying as much as $1.60 a litre, according to the Australian Competition and Consumer Commission.

ACCC chairman Rod Sims says concern about the global supply of crude oil had pushed up oil prices, with those rises being passed on at the pump.

"Unfortunately, the international factors pushing up wholesale petrol prices mean that these higher prices are being passed on to Australian motorists at the petrol bowser," he said in a statement on Tuesday.

Drivers were urged to use fuel price websites and apps to shop around.

Average unleaded petrol prices (March-June)

Perth: 140.9cpl

Sydney: 140.0

Melbourne: 141.1

Brisbane: 144.4

Adelaide: 140.0

Canberra: 148

(Source: comparethemarket.com.au)