The fishing company which owns a ship that caught fire in Lyttelton says the blaze could have been caused by contractor repair work.
Sandford Ltd says the Ocean Breeze caught fire on Wednesday while in dry docks during its first week of general repair and maintenance.
General manager of operations Greg Johansson says the fire was limited to a relatively small section below decks.
Mr Johansson says the 60-metre vessel, which fishes for Tuna in New Zealand and Pacific waters, usually has a crew of 22 on board, but no-one was in the area when the fire broke out.
The Fire Service says teams were on rotation overnight on Wednesday and at the height of the blaze 16 appliances were at the scene.