Six crews and two helicopters fought four separate blazes near the Heathcote River on Wednesday afternoon, which spread across an area of about 400m.
Tunnel Rd was closed between Ferry and Port Hills Rds and fire investigators were working to determine the cause.
No one was evacuated. However, a pregnant woman was taken to Christchurch Hospital by police after suffering a medical event near the fires on Tunnel Rd.
Nearby resident Alistair Campbell was looking out the window when he saw the smoke.
"Everything is dry, you can’t afford to have a fire.”
He said the fire was in a large paddock, where he believed there were horses and a stable.
Senior fire risk management officer Bruce Irvine said the blaze shows exactly how quickly fires can grow in the conditions, especially near the Port Hills."We saw how quickly this fire grew, anything like this is being taken very seriously and dealt with very quickly.
"We are going to hammer these with a lot of resources.
"We are ready, we are prepared for this type of event and all they (the public) have to do is give us a call as soon as they see smoke,” Mr Irvine said.
The entire Canterbury region remains in a prohibited fire season and yesterday’s blaze comes as fire chiefs warned the public to stay away from areas they may not be able to escape from if a major fire breaks out.
Days of hot temperatures late last month led to the warning, which encouraged the avoidance of areas with only one or two entry and exit points, such as Godley Head.
