Pump prices have increased twice this month, with motorists now having to fork out up to six cents more a litre for their petrol.
Experts say this is because of stronger crude oil prices, which are now edging close to US$60 per barrel, up from around US$50 two months ago.
The most popular petrol grade, 95-octane, is now priced at $2.19 per litre across petrol stations islandwide.
This is on the back of two price hikes - the first on May 7, when Caltex, Esso and Shell raised prices by up to four cents a litre. Singapore Petroleum Company (SPC) followed a day later.
Starting from a week ago, the four companies further increased their petrol prices by two cents a litre.
With the price hikes, other petrol grades are also more costly.
The 92-octane grade is now at $2.15 a litre, while prices for 98-octane range from $2.37 for SPC's Levo 98, to $2.75 for Shell's V-Power.
All prices are before discount.
Independent oil consultant Ong Eng Tong said: "Crude oil prices and petrol wholesale prices tend to go up concurrently, and crude has gone up quite a bit from about two months ago."