Oil companies should come clean about rises in the price of fuel, the AA says.
The driver advocacy group said yesterday that, by its calculations, the average margin on a litre of petrol and diesel was 4c higher than it was a year ago.
After staying steady in September, the price rose by 11c a litre in October, of which 7c was directly related to increases in GST and fuel tax.
The AA said the additional 4c increase was surprising given that crude oil prices had been relatively stable while the New Zealand dollar had risen against the United States dollar.
Spokesman Mark Stockdale said this should lead to a fall in pump prices.
"The New Zealand dollar has gone up, the crude price has gone up, so the import cost to the fuel companies has fallen in the last few days as a result of the exchange rate, so that's a saving we expect to be passed on to motorists."
He said fuel companies should also explain why price changes had become fewer and smaller than a year ago.
"Price-wise, the market doesn't seem to be as competitive as it once was. This is of concern and [the AA] will continue to monitor this situation."
He said it seemed to have worsened since Greenstone acquired Shell's New Zealand retail business in April.
Greenstone's Mike Bennetts denied that the market or his company had become less competitive on pricing.
The reduction in price movements reflected reduced volatility, with oil trading within a narrower price band this year than it had in recent years, he said.
BP's Neil Green said he believed the market was as competitive as it was a year ago, but there had been substantial costs imposed by the Government.
