Guard rails and posts on a main road over the Port Hills have melted and burnt away in the fires this week.
Residents watch the fires burn along Worsley Road and Cracroft, from Dyers Pass Road earlier this month. Photo: RNZ / Emile Donovan
Civil Defence said Dyers Pass Road was in good condition otherwise, but the guard rails and safety signs would need to be repaired or replaced.
It said one power pole was damaged and some trees needed removing.
Some rocks above the road were also destabilised in the fire, and a geotechnical assessment was needed.
Civil Defence said it planned to complete the work as rapidly as possible, because it was a key route, and many people were asking when it would reopen.
Nine homes were completely destroyed and two were partially damaged in the fire that scorched 2075 hectares of land.
Civil Defence said infra-red and thermal imaging drones used overnight had found lots of hot spots along the 35km fire perimeter.
Selwyn incident controller Mike Grant said the roots of trees in those areas were still burning, and they wanted to get them fully under control before warmer weather on Tuesday.
He said it was hoped the perimeter would be totally controlled by Wednesday or Thursday morning.
A total of 25 fire crews, or 150 firefighters, were working today.
Crews were working to cool the areas around residential properties in upper Summit Road and Worsleys Road.
The Fire Service said it was now working on a detailed map of the unburned vegetation within the fire area.
A spokeswoman for the Christchurch Adventure Park said the fire was still burning on the site, and they were expecting to find a significant amount of damage when staff were allowed back in.
She said the chairlift was damaged, and burnt trees around the mountain bike tracks would need to be cut down before the park could reopen.
Insurance assessors were on standby, and they did not know when they would be allowed back in or when the park would reopen.