The average price of unleaded petrol across Australia jumped by 6 cents to 134.3 cents a litre in the past week, representing the single biggest increase in two years, new figures show.
Petrol prices shot up by 9.1 cents in NSW, 4.7 cents in Victoria, and 12.5 cent in Tasmania, according to Australian Institute of Petroleum's latest weekly report.
Earlier this month, the Australian Competition and Consumer Commission urged motorists to fill up their tanks, predicting prices would leap in the wake of the Organisation of Petroleum Exporting Countries' (OPEC) agreement in December to cut oil production and with the Australian dollar falling against the greenback.
CommSec senior economist Savanth Sebastian said there may be a reprieve in coming weeks.
"In Australian dollar terms, the Singapore unleaded price, which we derive our fuel from, fell by almost $2.50 a barrel in the past two weeks and this should flow through to pump prices in around a fortnight's time," he said.
"The production cuts announced by OPEC and non-OPEC nations are now being enforced. The early indications are that producers are already notifying customers in Asia, Europe and the US of cuts to oil deliveries from January ... meaning higher pump prices in the medium-term."
He said filling up the tank with petrol was the biggest weekly purchase of a single item for most families.
"The average household fuel bill has lifted by $27 in the past five months to $161 a month - an 18-month high," he said.
In terms of metropolitan prices, Canberra suffered the biggest spike over the past week, with the average unleaded petrol prices going up by 14.1 cents.
The average price went up by 13.5 cents in Hobart, 11.3 cents in Adelaide, and 8.1 cents in Sydney.
Sydney motorists are being encouraged to use the NSW Government-run FuelCheck website and app to nab the best deals in their area.
For example, FuelCheck on Monday afternoon showed Metro Castle Cove, near Chatswood, was selling unleaded petrol for 129.9 cents a litre, while Coles Express Lane Cove was charging 144.9 cents. That's 15 cents difference.
NRMA spokesman Peter Khoury said petrol companies were "ripping people off".
"Not only did we not get to the low point of the cycle we were expecting before Christmas, but it didn't take very long for a number of the major service stations to increase their prices quite significantly," he said.
"Overnight, a number of service stations increased their prices to 144.3¢, which is way too high, the terminal gate [wholesale] price is 20¢ cheaper than that.
"None of the capital cities got to as low as we thought they would over Christmas."
