New Zealand Refining made a $5 million annual loss due to the strength of the New Zealand dollar and excess refining capacity in the industry globally, it says.
The nation's only oil refinery's 2013 result compares with the $30.9 million it made the previous year.
However the company beat its own target for cutting costs by 50 percent in delivering $6 million in savings, and it is promising a further $7 million this year.
Chief executive Sjoerd Post said two of the biggest drivers of the business were beyond the company's control - the exchange rate and over capacity in the oil refining industry.
"We have two big external variables that drive our results. There's the exchange rate, because our income is in US dollars, so we are actually short the New Zealand dollar in our results," he said.
As well, a lot of refining companies pre global financial crisis took investment decisions, because refining was very profitable and the impact of those decisions was becoming clear.
"China is still growing but not growing by as much as was anticipated during those investment decisions, so there is an element of over-capacity in the region in which we operate," Mr Post said.
However, the company had focussed on what it could control and had cut costs. It had a good plan, good people and just needed to ride the storm, he said.