A bushfire broke out on Wednesday and has since burnt through more than 650 hectares, destroying one home and causing mass evacuations.
It had been contained as of this weekend, with almost all residents allowed to return home.
However, firefighters were continuing to stamp out hotspots on old "skid sites" - left over from forestry logging operations - which needed heavy machinery to dig them out.
They would also be targeting additional hotspots identified by drones and a helicopter overnight and at first light.
MetService meteorologist Mark Todd said light winds were forecast for Sunday morning, but they would strengthen and swing northwesterly in the evening.
Severe gales were predicted for the Canterbury high country on Monday and a strong wind watch was in place.
Todd said those gales could cause concern for fire crews.
"We're not expecting severe gales to come down to the plains but there will be strong and gusty northwesterly winds in exposed places around the Christchurch area during the course of Monday as that front approaches."
Fire and Emergency NZ incident controller Steve Kennedy earlier said there was a chance some people would need to be evacuated again on Sunday due to the strong winds.
Riley said further evacuations were "the last thing we want to do" but the state of emergency would enable them to do so if necessary.
Kennedy said firefighters would be working to strengthen the containment lines on Sunday before strong winds arrived.
The fire had been contained within a 24-kilometre perimeter.
Crews wanted to make containment lines at least 50 metres wide, Kennedy said.
A helicopter with thermal imaging gear also flew around the perimeter of the fireground early on Sunday morning and detected additional hotspots.
There were 86 firefighters and other personnel at the site on Sunday, supported by diggers and bulldozers.
Five helicopters were also available.
There was still a possibility of flare-ups and firefighters were making the most of favourable conditions on Sunday morning, Kennedy said.
"It can look like it's out, and then we get the wind in behind it and it can spark up and flare off again."
Christchurch resident Lynette, who lives at the base of Worsley Spur, said the co-ordinated effort by emergency services had made her family feel safe.
"We have a really good community here and we've got a really active Facebook group that we'll talk on, and we just can't believe how amazing all the first responders and staff have been."
