A 100-metre stretch of Pitt Avenue, near the Veulalee Avenue intersection, was closed to traffic for about two hours from 9pm by two police cars while police conducted an investigation at a Pitt Avenue residence.

It is believed the injured man had been the victim of an assault about 6.30pm but police would not give details of his injuries or his age last night.

Senior Constable Stephen Burton said an incident had occurred in which a man had been injured and taken to the Launceston General Hospital.

"We have numerous people assisting us with our inquiries and those inquiries will continue throughout the night," Senior Constable Burton said.

"We have uniformed police, CIB and forensic squads at the scene of the incident and we are expecting investigations to take some time."

Senior Constable Burton said residents of the blocked-off area had remained in their homes, with returning residents refused entry to the area until about 11pm.

Police said later that they had blocked off the road while they identified the exact location of the alleged assault.