Petrol prices in Sydney have hit a new record with the cost of unleaded fuel reaching 171.9 cents a litre at some service stations.
Fuel outlets in various Sydney suburbs selling for different companies raised their unleaded price by up to 20 cents a litre on Wednesday.
"The prices we've seen today would be a record for this part of the pricing cycle in Sydney, and are not really surprising," Fueltrac managing director Chris Kable told AAP.
Fueltrac is an independent consultancy service which monitors fuel-related services for businesses in Australia and New Zealand.
"The Queen's Birthday long weekend a couple of weeks ago, on the Friday there was a $US11 spike in refined (oil) products and that basically has now flowed through to the Australian market," Mr Kable said.
"It's normal for that flow-on affect to take between 10 days and two weeks to reach consumers in Australia.
"But, (oil prices have) come down a lot since then so hopefully next week we may not see the same weekly high as we have seen this week."
Last week, economists predicted Sydney drivers would be hit with $1.75 a litre unleaded within a fortnight.
Mr Kable did not rule out a further price hike.
In Melbourne, there were similar price rises.
Petrol prices have begun to settle at almost $1.70 a litre at suburban service stations, but RACV government and corporate relations manager David Cumming said the price at one petrol outlet hit an all-time high of $1.72 on Wednesday.
"One service station hit 171.9 (cents per litre) today. They were flagging their intention to go up, but most of the big boys have settled at 169.9," he told AAP.
"There is still a bit of shifting going on at the moment so we will have a better feel tomorrow, but in my opinion the push today was totally and utterly unacceptable.
"It was well out of the normal range of increases."
Mr Cumming said the new record was forced by a 1.5 cent-per-litre increase in the wholesale fuel price, with further rises expected in the next two weeks.
"Don't be surprised if it goes much higher. We are having wholesale price increases every week, so we are seeing new records every week," he said.
"Once prices hit their peak hopefully they will start to go back (down) but that could be several weeks away."
In Adelaide, petrol prices also crashed through the $1.70 cents a litre barrier.
Fuel watch group MotorMouth said the highest price for unleaded fuel in the metropolitan area on Wednesday was 171.9 cents a litre.
The service said the average price for fuel was 158.5 cents while the lowest price was 153.9 cents.
There was no immediate relief in sight for local motorists with Thursday usually being the day Adelaide prices peaked.