Firefighters are worried an arsonist is at large after two suspicious fires this month, south of Dargaville.
A large scrub fire at Glinks Gully this week forced the evacuation of four baches and several campers at the local holiday park.
Principal rural fire officer Kevin Ihaka said there had been several deliberately-lit fires in the area in the past year or so, but this was the first time houses and people had been at risk.
He said anyone who noticed someone in the area beforehand without apparent reason, or hanging around the fire itself, should report that to the Dargaville police.
Mr Ihaka said both suspicious fires this month started in the middle of the night.