MotorMouth says wait to fill up

Fuel monitoring group MotorMouth has urged motorists to hang off as long as possible to get the best petrol prices ahead of Christmas.

It says three of the five capital cities - Adelaide, Brisbane and Sydney - have reached the high point in their price cycles in recent days.

"Prices are expected to fall each day from now right through to Christmas Day," MotorMouth managing director Alan Cadd said on Monday.

"So the longer you can hold off filling up your tank the better for your hip pocket."

MotorMouth said Sunday's average unleaded prices for Adelaide, Brisbane and Sydney were 133.3c, 134.3c and 132.2c.

Melbourne motorists were already doing much better with average pump prices of 115.5c.