Half year profit at Z Energy fell sharply after subdued economic activity reduced demand.
However, the fuel retailer says its gross earnings rose as the higher price of oil improved margins.
Z Energy chief executive Mike Bennetts says the company kept margins high despite high oil prices and intense competition.
Z Energy, which is owned by Infratil and the New Zealand Superannuation Fund, made a profit of $2.3 million in the six months to September, a decrease of 90% compared with the same period a year ago.
The company blames that on changes in oil prices which affects the value of its inventory.
However, gross earnings rose 17% to $96.8 million, despite motorists buying less fuel due to higher prices and intense competition from rivals.
Petrol sales fell 7%, which Z Enegy also blames on closing stations to change from the Shell to Z Energy brand.
Fuel margins picked up and profit equated to 2.6 cents per litre, compared with with 2.4 cents.
Looking ahead, Z Energy expects conditions to remain challenging and is still forecasting full year gross earnings of between $185 million and $200 million.