A plantation fire that blazed through Pines Beach in north Canterbury yesterday is being treated as suspicious.
Police are now asking anyone who may have noticed any suspicious activity in the area to come forward.
The blaze began in a plantation forest area 300m north of the car park at Pines Beach, 4km east of Kaiapoi, just before 2pm yesterday.
A helicopter equipped with a monsoon bucket and 21 fire engines battled the fire, which at its peak saw the evacuation of 40 nearby homes.
Residents were allowed back into their properties at 6pm last night after emergency services managed to contain the fire, and the cordon was reduced to encompass the bush and plantation area, acting Inspector Phil Dean said.