Last week's fires have destroyed a pine plantation which offered flooding protection to land near the Waimakariri River.
The blaze, one of a series of fired late last week, broke out near Thompsons Rd, West Melton, on Friday afternoon. It destroyed 15 hectares of Environment Canterbury-owned land planted with pine trees.
An Ecan spokeswoman said the pines were about 10 years old and were planted as part of a flood protection scheme.
"In that particular part of the river there are secondary stopbanks as well as the primary ones, so residents do not need to consider themselves any more at risk."
She said the stopbanks increased protection in the event of flooding where the Waimakariri River flow reached 6500 cubic metres a second. Its usual flow was 80 cubic metres a second.
The cost of the damage was being assessed, she said, and the cost of replanting the pines would be paid for from insurance.
The insurance company would decide whether it would try to recover costs from a third party if anyone was found to be responsible for starting the fire.
- Fairfax Media