THE petrol price is likely to rise by more than 10 cents a litre on September 1, the Department of Minerals and Energy said on Tuesday. The department’s petroleum director, Theunis Burger, said consumers have been paying an average of nine cents a litre too little for their petrol over the period July 26 to August 13. At present, the underrecovery rate stood at about 13 cents. The prices of diesel and paraffin are set to rise by the same margin. A final increase will only be determined after August 26, when all the figures have been processed, Burger said. Burger said he hopes this would be the last big adjustment this year.