Two fires in the Wenita Forestry block in Kaitangata on Thursday are being treated as suspicious and are under police investigation, Department of Conservation deputy principal rural fire officer Trevor Mitchell confirmed yesterday.
Mr Mitchell spent four hours at the scene of the fires on Wangaloa Rd, eliminating possible causes.
"We look at how the fire burned, which indicates where it started, then we look at where it started . . . We have located the areas of origin."
Mr Mitchell said the investigation had ruled out lightning, sparks from vehicles and cigarette butts as methods of ignition.
"We can't establish how they started . . . police are investigating the cause".
Forty firemen and crews from Wenita Forests and City Forests were called to the fires just after midnight on Thursday, and managed to contain the main fire in a 5ha area.
Kaitangata chief fire officer Kevin Sutton said fire crews would be monitoring the scene last night.
"Fire gets into the roots of trees and it can smoulder away there for days."
They would continue dampening down hot spots, he said.
