Rising oil prices and shrinking margins have slashed the annual profit of the operator of the Marsden Point oil refinery by more than two-thirds.
Refining New Zealand has reported a profit of $47.2 million for the year ended December compared with $150.8m the year before.
The company had a stronger second half as it processed a record amount of fuel and had an increase in margins.
The chief executive Sjoerd Post said the result is strong but the previous year had been a "trophy year" because of exceptionally weak oil prices and strong margins.
"This strong result shows that operational reliability, quality fuels production and pursuing revenue growth are critical to continuing to delight our customers and to maximise returns from a healthy margin environment."
Mr Post said the refinery was also showing the benefit of its upgrade of a couple of years ago which was boosting its processing margins.
The tourist boom and record numbers of flights into Auckland had also increased demand for aviation fuel.