An accidental “mishap” with a vehicle is believed to have started the fire in the central plateau, which is now fully contained.
Fire and Emergency New Zealand incident controller Renee Potae told media police had informed the organisation they had made good lines of inquiry as to how the fire started.
“It does seem to be unintentional, a misstep with a vehicle basically.”
In a further update this afternoon, Fire and Emergency New Zealand said the fire was fully contained.
Potae praised the efforts of everyone involved today.
“We will still have a presence tomorrow, with three ground crews, one tanker and one helicopter at the fireground.
“We’ll work through tomorrow with the aim of handing the incident to the Department of Conservation on Thursday,” Potae said.
At 1.30pm the fire’s size was 296ha, down from 322 this morning, with an 8.5km perimeter.
Fire and Emergency will continue to work with police to investigate the fire, she said.
Department of Conservation (DoC) operations manager Libby O’Brien said some parts of the Tongariro National Park are closed because of the fire.
DoC wants to reopen it as soon as it is deemed safe by Fire and Emergency and State Highway 47 reopens, she said.
O’Brien said she is not aware of any structural damage to the track, but all of the trails from Whakapapa Village have been closed as a precaution.
Mangatepopo Hut is closed and visitors staying in Waihohonu Hut have been helped back to Whakapapa Village.
O’Brien said the park will “hopefully” reopen to visitors tomorrow.
“But we will have to make that call potentially later this evening.”
Ngāti Hikairo ki Tongariro has extended the rāhui from the previous fire to all affected lands.
Ground crew and helicopters have been battling the fire throughout the day.
Earlier, Fire and Emergency said dozens of firefighters and five helicopters were at Tongariro National Park this morning to tackle the large vegetation blaze.
Mild conditions overnight helped firefighters keep the fire to 322ha.
Four helicopters would be using monsoon buckets today and a fifth would co-ordinate the air attack.
Planes were on standby if needed, the service said.
The air fleet would help 30 firefighters on the ground.
Three crews of firefighters dealt with a flare-up overnight.
Fire and Emergency operations director Brendan Nally told Herald NOW things were “looking quite good this morning”.
He said the wind was moving around “a little bit”, but not as much as when a large vegetation fire burned thousands of hectares in Tongariro National Park last month.
Temperatures would be in the mid-20C range in parts of the area today, which would make it tough for fire crews, he said.
“There’s an outside chance of a little rain but it won’t be significant enough to really help.
“So it’ll be our helicopters and [planes] that will do the damage today.”
SH47 between SH46 and SH48 was closed because of the fire.
The New Zealand Transport Agency advised drivers to allow extra time for travel.
Southbound motorists should detour via SH1 and SH49, with the reverse applying for northbound travellers.
UPDATE 7:30AM
— NZ Transport Agency - Central North Island (@nztacni) December 8, 2025
SH47 remains CLOSED between SH46 and SH48. Detour via SH49 and SH1.The next update will approximately 12pm today, Tue 9 Dec. ^EH https://t.co/h7UIYYMyzS
One of the fire flanks had come up on the burned-out area of last month’s fire, which had allowed crews to concentrate resources on the fire’s other flank, Nally said.
Fire and Emergency crews were alerted about 1.10pm yesterday to the blaze on the eastern side of SH47.
Yesterday, Nally said an investigation was underway, with initial indications the fire was not arson.