Same fire bug has lit four blazes: police

Another house has been destroyed by fire in a small community outside Hobart, with police saying the same arsonist has lit four blazes.

The latest fire destroyed an unoccupied holiday house in the beachside suburb of Primrose Sands overnight.

During the past six weeks three dwellings and a caravan in the hamlet have been destroyed, with each started in similar circumstances.

"This is a small community and these incidents are having an obvious impact," Senior Constable Ben Duffey said on Tuesday as he appealed for public information about the fires.