Fire crews have done a "good job" at controlling the fire on Saturday, but the fire is far from out, Christchurch City Council warns.
In an update sent out on Sunday morning, Civil Defence said that although there is some drizzle, dampness could dry out this afternoon with winds expected to rise.
The ground temperature within the fire zone can be between 100 and 500degC, and forecast warm temperatures and windy conditions could result in fires reigniting or spreading.
Fighting fire with machines
Heavy machinery is being brought in to put out the remaining embers.
Incident controller Richard McNamara says while there have been plenty of aircraft dropping water, that's not enough to put it out.
"Aircraft activity will only knock the heat out of the fire; it won't actually put it out. You've got to dig the fire out, you've got to scrape it out, you've got to hose it down to get it out."
Twelve helicopters and three fixed-wing aircraft will continue fighting the fire from the air.
A total fire ban remains in place across the Canterbury region.
Civil Defence says the priority for Sunday is to reduce the cordoned area around the fire and allow evacuated residents back into their homes where it is safe to do so.
Temporary access for residents in controlled areas
Around 40 residents queued on Hoon Hay Valley Rd as the cordons temporarily lifted. One by one, the residents were allowed access.
One resident told Newshub she is desperate to see whether her cat is OK. Another has lost his house and hasn't seen the damage yet. He has nothing but a car boot full of possessions.
The number of properties evacuated is at 150, as of Sunday morning.
Entry is restricted to adults, and residents will need to register with authorities at sign-in points at the bottom of the hill on Kennedys Bush Rd and at 51 Hoon Hay Valley Rd. Registered residents are allowed home to retrieve essential items until noon on Sunday. Civil Defence has extended the window of access in recognition of the short notice.
Civil Defence says people who are concerned about any animals left behind - especially dogs - should provide details to firstname.lastname@example.org.
Good news follows evacuation separation
On Saturday afternoon, Kennedy's Bush Road resident Kandi Hamilton Francois was allowed back home to check on her two alpacas. She'd had to leave them behind when the area was evacuated.
She'd left the gate open for the pair, just in case the fire reached the property.
But the pair didn't run away.
Ms Hamilton Francois told Newshub that the alpacas "were anxiously waiting up on the driveway by the house".
"They were very happy to see us and even more happy to get back into their paddock and have some pellets."
Areas of Port Hills closed by council
All open areas and walking and biking tracks in the Port Hills will be closed by the Christchurch City Council on Sunday.
Christchurch Civil Defence says signs will be erected to advise people of closures.
"These restricted zones cover all tracks and open areas in the Port Hills, including Victoria Park and the Rapaki, Mt Vernon and Huntsbury tracks."
The restrictions are likely to be in place for several weeks.