Hope you enjoyed it while it lasted.

Petrol prices have returned to their pre-price war heights with the national average price of unleaded rising 3.7 cents in the week to March 7.

Fresh data from the Australian Institute of Petroleum shows the price of a litre of unleaded fuel has risen everywhere except the Northern Territory.

In Victoria the price rose 5.4 cents and only South Australian motorists copped worse with a 5.6 cent rise to an average of $1.26 a litre.

Last week the price changes were smaller and were falls rather than rises.

CommSec economist Savanth Sebastian blamed the sudden rises on profit margin pressures for the major oil companies.

"The heavy discounting was clearly an unsustainable scenario," Mr Sebastian said in a statement on Tuesday.

"And after selling petrol for what was virtually below cost, petrol stations are once again increasing margins in an attempt to remain profitable."