Fire crews and resources such as machinery have been stretched as the Fire Service and rural fire crews fought several fires at a time, he said.
The Department of Conservation (DoC) has joined with fire authorities and the police in calling for help from the public regarding the lighting of unlawful and suspicious fires.
There were three suspicious fires in five days on conservation land at Pouto Peninsula, south of Dargaville, on January 4, 5 and 7.
The fires were eventually contained and no homes were affected, but about 10 hectares of reserve land were burned, destroying native plants and wildlife and endangering firefighters.
DoC operations manager Geoff Woodhouse has appealed to members of the public to report any suspicious behaviour, or if they have information relating to the Pouto fires to contact Dargaville Police.
Anyone found responsible for causing unlawful fires can be convicted and subject to a term of imprisonment.
Information could be found at www.northerrfa.org.nz.