The Automobile Association (AA) has challenged fuel companies to slash their prices more dramatically, describing the recent cuts as miserly.
The prices of petrol and diesel have tumbled for the third time in three days - the 22nd consecutive drop since October.
BP this morning cut the price of 91 to $1.729 per litre, while Z Energy put it at $1.739.
Both companies dropped the price of diesel to $1.079 a litre.
AA petrol spokesperson Mark Stockdale said they could afford to slash the price more, given significant drops in the global commodity price.
He said they were boosting their profits by not passing on all of that reduction to motorists and the current prices were unjustifiable.
"They're hanging on to some of that cost reduction. That's enabling them to make more money. They're not passing it on as quickly and the size that they could to motorists," he said.
"We think that's being a bit miserly, really."
But Zed Energy rejected that and said it was carefully monitoring the global price and adjusting its retail price accordingly.
"Ultimately, we want to give our customers competitive prices but we don't want to have to drop the price by say six cents one day only to have to put it up again the next day," Z spokesperson Sheena Thomas said.
"So we're basically waiting to see what happens with the barrel prices and we're continuing to pass them through sooner rather than later."