Police are investigating a suspicious unit fire at Trevallyn last night.

Around 2.00am emergency services responded to reports of a unit on fire on Pitt Avenue.

Tasmania Fire Service crews extinguished the fire which had fully engulfed the house.

A fire scene examination will be undertaken this morning.

Anyone with information is asked to contact police on 131 444 or Crime Stoppers on 1800 333 000 or at crimestopperstas.com.au. Information can be provided anonymously