The AA says many service stations in the North Island are effectively selling petrol below cost - by discounting prices by 20 to 30 cents a litre.

However, on the whole, the motoring organisation says motorists will be disappointed with fuel prices, with are rising on the back or higher commodity prices.

The AA PetrolWatch spokesperson Mark Stockdale says, despite a recent report showing that fuel companies are as quick to drop prices as they are to raise them, latest price increases have come within 24 hours of a commodity rise.

He believes it would be fairer for fuel companies to wait two or three days to see where commodity prices settle before adjusting retail prices here.