Motorists are in for another shock at the bowser with petrol prices set to rise tomorrow by up to 12 cents a litre.
FuelWatch advises motorists to fill up today to avoid the price hike.
Most BP, Caltex and Coles Express sites will increase the price of unleaded petrol by 12 cents per litre to just under $1.63.
Caltex Woolworths and Gull sites are set to charge almost $1.62 per litre and most Peak stations will be charging almost $1.61.
Tomorrow's average metropolitan price will be $1.60 cents per litre, but motorists who are prepared to shop around will find some outlets selling unleaded petrol for less than $1.50.
Thursday and Friday are the most expensive days to fill up, Fuelwatch says.
Today's cheapest petrol is at Gull stations in Bellevue and High Wycombe, Caltex in Maddington and Coles Express in Duncraig, Mount Lawley and Warwick.
The cheapest petrol tomorrow will be at Caltex in Midvale ($1.46), Murdoch and South Lake (both $1.44) and Coles Express in Duncraig, Mount Lawley and Clarkson (all $1.43).