About 30 firefighters are continuing to work in sweltering conditions to dampen down hotspots at the Ahipara fire.
The blaze, which started on the evening of December 29 on a ridge above town in the Gumfields Historic Reserve, swept through 56ha of scrub and bush and forced the evacuation of up to 100 homes.
It was 90 per cent contained by mid-morning on December 30 when the number of helicopters in use was reduced from six to three.
Given current high temperatures and low humidity, however, flare-ups remain a danger.
All residents were allowed to return home on Wednesday evening but Wharo Way and Gumfields Rd were reopened to residents only, who had to show ID to get through cordons manned by police, private security guards and iwi members.
They were instructed to be ready to evacuate if necessary.
Incident controller Rory Renwick said on Thursday firefighters were concentrating on putting out hotspots near the fire perimeter, because they posed the biggest risk of spreading into unburnt areas if they re-ignited.
The terrain was so steep in places they had to cut tracks to reach the hotspots, he said.
The situation was ''looking positive'' but the perimeter was large and there was still a lot of work to do. Helicopters were being kept on standby in case they were needed again.
Two investigators were working to establish the cause.
Renwick said Fire and Emergency NZ was grateful to everyone who had provided food and accommodation for evacuated residents and fire crews, donated food or other items, or had helped by providing equipment or allowing access to the fire ground.
Meals and accommodation were provided, among others, by Roma Marae and Ahipara Rugby Club, with the Salvation Army, Te Rarawa, the Kaitaia-based Rapid Relief Team and many others donating food.