Poor competition keeps fuel prices up: RBA

Fuel refiners and retailers have been able to widen their margins because they aren't facing enough market competition, the RBA says.

A lack of competition is to blame for petrol prices not falling, the RBA says. (AAP)

A lack of competition is to blame for petrol pump prices not falling as fast as global oil prices, the Reserve Bank says.

Reserve Bank of Australia assistant governor Christopher Kent says refiners and retailers have been able to widen their margins because they aren't facing enough market competition.

"Ultimately competition is what bears down on businesses margins and their ability to move those margins around, so it has to be, I don't see any other reason," Dr Kent told a parliamentary committee hearing on Friday.