Fire crews in Bluff, south of Invercargill, have spent the wee hours of this morning battling a blaze at a large warehouse.

Fire and Emergency New Zealand was alerted to the blaze at South Port Bluff, around 11.30pm.

Shift manager Andrew Norris said the warehouse, which was around 7,000 square metres, was engulfed in fire upon their arrival.

"At the peak of the fire we had six fire engines and around 30 firefighters battling the blaze," he said.

The firefighters had the blaze under control by dawn.

There were no injuries reported as a result of the fire.

The warehouse contained palm kernel - a type of stock that Norris said could heat up when stored in large quantities.

Norris said a Fire and Emergency New Zealand staffer would likely be back at the scene this morning to check all was well.

The fire was not being treated as suspicious, he said.