Petrol companies have dropped prices, taking the cost at the pump to under $2 a litre for the first time since January.
BP, Z Energy, Mobil, Caltex and Gull on Thursday lowered prices by 4 cents per litre and diesel by 3 cents.
The companies say the drop is due to the latest fall in the price of oil on international markets.
On Thursday, 91 octane was being sold at $1.999 per litre and 95 octane at $2.079 and BP and Z outlets while diesel cost $1.409 - $1.419.
The Automobile Association's petrol watch spokesperson says the drop in price is fantastic for motorists - but should have happened a week ago.
Mark Stockdale says petrol companies were benefiting from the high exchange rate last week and were not passing it on to motorists.
However, Caltex says the decrease could not have happened any sooner.
Sharon Buckland, the spokesperson for Chevron New Zealand which owns Caltex, says the Automobile Association's comments are incorrect and petrol prices are not solely based on the state of the New Zealand dollar.