The fire at Tiwai Peninsula near Bluff burned through the night after it began just after 7pm yesterday.
The fire has now claimed 130ha of native scrub.
Fire and Emergency New Zealand (FENZ) community and engagement co-ordinator Sally Chesterfield said the fire was contained early this morning, but given how dry the area was there was a risk it could go out-of-control again.
Firefighters and six helicopters with monsoon buckets were still involved in putting out the fire and a fire crew would continue to work overnight to dampen down hot-spots and ensure the fire did not flare-up again.
The fire no longer posed a threat to the electricity supply to Tiwai Point aluminium after earlier spreading close to the main lines which feed it.
Overnight nearly a dozen fire crews battled the blaze as well as two aircraft using night vision googles because of the proximity of the smelter.
Mr Dunn said crews would be rotated in coming hours just before the blaze hit the 12-hour mark.
Mr Dunn said the fire was difficult to reach as there were no roads into the area. Four helicopters with monsoon buckets were first to tackle the blaze.
"Its been a long fire. We've been trying to protect the Tiwai smelter, which they're doing a great job of and firefighter operations will just continue," he said.
Bluff Resident Rosie Coyle said "most of Bluff" was out watching the "really intense" fire.
"People were out watching it, a lot of people went up to the lookout to watch but I could see it from my living room window.
"I had a clear view of it from upstairs. You could see the fire moving closer to the Tiwai smelter and you felt really anxious watching it.
"The flames were really high.
"They seem to have got it under control now but it was really intense," Ms Coyle said.
