ADM New Zealand general manager Ross Bowmar said the damage to the warehouse, which ADM leased from SouthPort, had not been as bad as initially thought.
Six fire engines with 30 firefighters were deployed to fight the January 18 blaze at the port.
An investigation has been completed, but while the details of that investigation have not yet been released, the fire was not deemed to be suspicious.
The warehouse was reportedly filled with palm kernel, prompting one firefighter to comment that the blaze could have been caused by the stock feed heating up and catching alight.
Mr Bowmar dismissed this theory, without going into details of what caused the blaze.
"The fire had nothing to do with palm kernel. It was what we call a machine fire."
He said he could not disclose what the blaze had cost or more details on the cause.
"It is still under investigation, but it is not as bad as it first appeared.
"The roof's been repaired and we are back in operation.
"It is business as usual."
