A large scrub fire in the Canterbury high country is continuing to spread though very slowly.
The fire, near Castle Hill, has burned through 300 hectares of vegetation.
Fire and Emergency shift manager Andrew Norris said five helicopters and 38 ground crews are in attendance.
He said the focus today is on reinforcing the fire's perimeter and damping down any hot spots.
Most of the work has to be done by air because of the rough terrain, Norris said.
He said the fire is not contained but is not burning vigorously.
"Those helicopters and crew will be working to secure the containment lines, strengthen those and to move through the middle where they will continue 'hot-spotting' which is locating and extinguishing all hot spots of trees, logs and any other vegetation."
He said the work is very difficult for the ground crews, because of the steep terrain.