Petrol stations should have cut fuel prices last month to reflect a drop in international commodity prices, the Automobile Association says.
AA petrolwatch spokesperson Mark Stockdale said after falling two cents a litre early in April, petrol and diesel prices later rose by four cents a litre.
At the end of April, one litre of 91 octane cost $2.18/litre, while diesel reached $1.50/litre at most service stations.
Oil companies should drop their prices by two cents a litre, given falling commodity prices and the high New Zealand dollar, Mr Stockdale said.
The AA also wanted the Government to make it mandatory for fuel companies to publish the price of all fuel they sold, not just 91 octane and diesel, he said.