The Automobile Association is calling for a drop in petrol and diesel prices after big rises during October.
Petrol prices climbed 11 cents, partly due to increases in the Goods and Services Tax (GST) and excise tax.
Rising oil prices also contributed to higher costs at the pump.
But AA PetrolWatch says oil prices have recently dipped and the New Zealand dollar has strengthened.
Spokesperson Mark Stockdale says that means oil company margins are high and those effects should be passed on to consumers.
Mr Stockdale says he is concerned the retail petrol and diesel market is becoming less competitive.