The auto liquefied petroleum gas ceiling prices for dedicated LPG filling stations will be revised to range from $3.33 to $3.71 a litre in September, representing a rise of about three to four cents a litre, the Electrical & Mechanical Services Department says.

The department said the adjustment reflects the movement of LPG international prices in August. It is made according to the terms and conditions dedicated in the stations' contracts.

The ceiling prices are adjusted according to a specified pricing formula. The formula has two elements - the LPG international price and LPG operating price. The LPG international price is the LPG international price of the preceding month.

The LPG operating price will be adjusted on the first day of February each year according to the movement in the Composite Consumer Price Index in the previous year.