Around 90 percent of the fire perimeter area in Christchurch's Port Hills is considered to be controlled, firefighters say.
The definition of "controlled" is bare earth or blacked out ground for at least 10 metres.
However, the Fire Service says there are many hotspots that could flare up under some conditions.
Overnight, crews will continue to monitor and patrol the area, and drones will be back in the air to gather thermal and infrared hotspot imaging information.
The perimeter is around 30km and covers more than 2000ha, and about 100 people have been there on Thursday in both land-based and aerial operations.
Crews have also been working to identify any unburnt vegetation and to reduce the fire risk by creating fire breaks or removing vegetation.
Meanwhile, authorities say free GP visits are being offered to people affected by the fires, at the discretion of their general practice team.
The offer, which includes people who have been working on fire control and recovery operations, is for a two-month period from February 13, the day the fires started.
The fires destroyed at least nine homes, according to Civil Defence figures. They also led to residents being evacuated from about 400 homes.