Police say a man they are searching for following a suspicious death in a rural Tasmanian community may be armed with a knife and should not be approached.

Police are treating the death of a man whose body was found in a house at Reedys Marsh near Deloraine as suspicious.

Emergency services were called to the scene on Larcombes Road about 6pm on Tuesday.

Two men and a woman are in custody and are assisting police with their inquiries.

However authorities searching the area for another man they say may have camouflage paint on his face and may be armed with a knife.

Local residents have been asked to ensure their properties are secure and to immediately contact police or call triple zero.

Police have asked Larcombes Road residents to secure their properties. Photo: ABC News

The rescue helicopter is involved in the search.

Earlier, police said they believed the people were known to each other and the offender may have been armed with a “bat-type weapon”.

CIB and forensics officers are at the house at Reedys Marsh.

Police said the examination was expected to take some time.