The Office of Fair Trading (OFT) is due to release a review into whether reductions in the price of crude oil are being passed on to motorists.
The OFT will then decide whether to launch a full investigation into fuel prices.
Edmund King, president of the AA said it was time the OFT investigated the fuel industry:
"The Office of Fair Trading decides soon whether to launch an investigation into fuel prices, hopefully tackling the fuel industry's treatment of drivers, consumers and businesses."
Brian Madderson, from the Petrol Retailers Association (PRA), called on the OFT to launch an investigation into the wholesale market rather than target petrol stations.
More top news
The Bank of England has launched a secret project looking at the economic risk to Britain if the country votes to leave the European Union.
The actress and The Only Way Is Essex star Mark Wright will become husband and wife over the Bank Holiday weekend.
The annual event has earned a place in the record books ahead of the grand final of the 60th anniversary show in Austria this evening.