Fire and Emergency believes arson is behind two scrubfires in the Far North over the past fortnight.
The two fires around the Karikari Peninsula followed a blaze at nearby Kaimaumau, where fire crews have only just finished mopping up a fire that spanned 2800 hectares.
Te Tai Tokerau manager Wipari Henwood says the fire that started yesterday afternoon near Lake Ohia has burned 10 hectares, and it appears there are three ignition points.
He said Northland brigades were having their busiest summer in years.