Motorists could be saving up to 20 cents a litre if it wasn't for the diving dollar, an economist says.
While global oil prices have been dropping, the national average price of unleaded rose by 1.5 cents this week, fresh data from Australian Institute of Petroleum shows.
"The weaker Australian dollar is behind the turnaround in motorists' fortunes," Commsec equities economist Savanth Sebastian said in a briefing note.
"Had the Aussie remained at the levels it was at two months ago (US98 cents), motorists would be enjoying considerable savings at the petrol pump.
"Taking into account the sharp falls in global oil prices, current pump prices, and the Aussie dollar, motorists could have enjoyed saving in the vicinity of 20 cents a litre had the domestic currency remained at 98 cents against the greenback."
The most expensive capital city remains Darwin, where motorists are being charged $1.61 per litre.
Brisbane, thanks to a state government tax break, remains the cheapest city to buy unleaded at $1.46.
There was room for motorists to have some optimism, Mr Sebastian said.
"Global oil prices are likely to remain at lower levels with slowing global growth ensuring weaker demand for oil based products".
"In fact, over the last month, US demand for oil-based products has continued to decline, down 3.5 per cent on a year ago."
