The New Zealand Refinery produced 6.5 million barrels of oil in June and July, operating close to full capacity.
The average gross operating margin was $US4.83 a barrel in the two- month period, and the processing fee totaled $35.6 million.
The country's only refinery says the margin has fallen significantly because of a fall in demand for fuel and an increase in global refining capacity, while a strong New Zealand dollar reduced returns from processing fees.
