Firefighters will continue to focus on strengthening the fire break around the perimeter of the Port Hills fire today.

Incident Commander Dave Stackhouse says the fire has burnt through 650 hectares, with a 14km perimeter. The fire is now 70 per cent contained.

Today there are 95 Fire and Emergency staff on site, alongside 22 trucks and tankers, 12 helicopters, two fixed wing aircraft and five diggers.

Weather conditions and a light easterly wind will assist with operations today, Dave Stackhouse says.

"Today we are going to hit it hard with a bigger number of firefighters to really focus on strengthening fire breaks. It is still very much an active fire ground with heavy machinery and helicopters at work," he says.

"Firefighters are working incredibly hard to get to a position where we can allow residents to return to their homes and get some normality, and this remains our priority.

"Today there will be a heavy presence on the Summit Rd and Worsley Spur as crews focus on containing the fire."

Dave Stackhouse reminds the public that the Canterbury region is in a prohibited fire season.

"I encourage the public to be mindful of this. Yesterday we had to pull resources from the Port Hills fire so crews could attend other fires in the area," he says.

"Take great care with any activities that could cause any sparks and start another fire and call 111 straight away if you see any fire or smoke."

The joint investigation with New Zealand Police into the cause and origin of the fire is continuing.

Until the investigation is complete, we will not be making any comment about how the fire started, or any findings.

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