The Tasmania Fire Service alerted police to a series of deliberately lit fires on Friday night after it had attended more than five in the area.

Fire service acting station officer Tony Johnson said the fires weren't too serious, but they had the potential to be extremely dangerous.

``It's not big as far as bushfires are concerned, but it's big considering there's a lot of ground to get around when you've got houses around,'' he said.

``At this time in the afternoon the temperatures up to 29 degrees already and it's when the relative humidity drops out that it becomes quite volatile.''

The most recent fire in the area was one reported at the end of Naranka Street just before 3.30pm yesterday.

Seven engines had to attend the fire that had spread across four hectares of land and it took about an hour before it was contained.

``It may only look like some rubbish bushland but it has potential over the back where some of the vegetation is a bit closer to houses,'' Mr Johnson said.

A gully also runs down the back of the area where the fires have been lit which leads straight to Vermont Road.

``That's got potential (to be dangerous) as well,'' Mr Johnson said.