Z Energy hopes to get its biodiesel plant producing commercial fuel within the next two months after months of delays.
The company had hoped to start supplying partners from the plant at Wiri in the second half of last year.
However, the $22 million operation - which will produce biodiesel from animal fat - has struck teething problems.
Z's general manager of supply and distribution, David Binnie, said while it had successfully produced a trial batch there had been some electronics problems in the control centre and some pump seal failures.
Some problems were exposed by a power cut in the Wiri area.
""The plant came down safely as it's planned and the control system didn't react in the start up as we wanted it to,'' he said.
We're making some more modifications to make sure they're more reliable than what they were. We want to do it right and safely.''
When complete the plant will produce up to 20 million litres of pure biodiesel which will be mixed with mineral diesel to produce a 5 per cent blend. It will be sold for a premium of around 2 cents and already some big users including Fonterra, Fulton Hogan and New Zealand Post had signed up.
Binnie said Z was working closely with them following the delays which he said were not unusual in a new plant.
Binnie said the trial run produced 180,000 litres before Christmas.
'The pleasing thing we got the product through the plant and it worked.'''