"That fire has burned uncontained simply because there's no access to it.
"In the early hours of this morning we basically maintained a watch and kept an eye on it from a distance...There's baches scattered around the area. A couple of them were threatened but not damaged.
"We did evacuate people from one bach just as a safety precaution."
He said it was not being treated as suspicious.
Selwyn District Council deputy principal rural fire officer Douglas Marshall said it was believed power lines crossing each other in the "blustery" wind had caused the blaze.
About 30ha of scrub and another 5ha of pine trees and a wood shed were destroyed in the fire, he said.
Mr Marshall said it was now contained but firefighters would be at the site until at least the early afternoon.
A helicopter was used for observational purposes this morning and three more were on standby but did not need to be used, he said.
"When you get blustery winds with power wires it does happen from time to time that they will arch and cause a spark.
"What was challenging here was that the fire was reported at 4.15 this morning so it wasn't safe to put firefighters either on the ground or into the air due to the darkness and the heavy winds that were up there.
"The plus side was that it allowed the fire to burn down to an area where we could then attack it and contain it reasonably easily, and do so in a safe manner."
About 25 firefighters were now monitoring the blaze, he said.
