The fire in pine trees near Sawyers Arms Rd was reported at 10.20pm and grew to 30m by 30m in size.
Three fire crews from Harewood, Spreydon and West Melton attended and a tanker was sent from Brooklands Fire Station.
A Fire and Emergency New Zealand spokesman said the blaze burnt through logs and other off-cuts.
It was being treated as suspicious. A police spokeswoman said enquiries into the fire are ongoing.
Crews remained at the scene, near the intersection with Johns Rd, until just after midnight.