"There is always the risk that further evacuations could be required."
Selwyn fire controller Rob Hands says the blaze was "complex", with different fuel types and different terrain.
By mid-afternoon today, when temperatures are well into the mid-20s, firefighters should be able to identify hot spots.
There have been minor flare-ups this morning and fire crews are now focusing on those around residential areas.
Senior geotechnical engineer Ian Wright said the risk of rock fall is low.
Parks operations manager Kay Holder said some parks will remain closed while fire operations are under way.
Two hundred firefighters are on the ground and 46 evacuated properties are still behind cordons.
It's a complex fire with different fuel types and different terrain, Selwyn incident fire controller Rob Hands said.
By mid afternoon today, with temperatures well into the mid-20s, firefighters should be able to identify hot spots.
There has been some minor flare ups this morning and fire crews are now focusing on them now around residential areas.
Senior geotechnical engineer Ian Wright said the risk of rock fall is low.
Kay Holder, operations manager parks, said some parks will remain closed while fire operations are underway.
The decision to extend the state of emergency covering Christchurch and Selwyn came after Dalziel and Selwyn Mayor Sam Broughton took advice from Rural Fire, Fire Service, police and Civil Defence.
"The fire is still being fought on the ground and in the air," Dalziel said.
"The environment remains volatile inside the controlled area.
"The fire is not out and there are extensive hotspots to deal with.
"There is always the risk that further evacuations could be required."
The extension automatically lasts for seven days but could be terminated earlier.
