No sign of Tas man missing for two months

Recent flooding had given police renewed hope of finding evidence of a Tasmanian man missing for two months.

But after several hours using a low-flying helicopter to scour a river and its banks nearby where Ben Plowright was last seen, a search on Thursday again proved fruitless.

The 20-year-old Launceston man was last seen on May 30 leaving a party in the township of Perth, south of the city, and the search since has been the most extensive ever seen by Inspector Scott Flude.

"There have been a number of floods in the area and we thought it timely to conduct a search using the helicopter," he told reporters.

"Unfortunately we didn't find anything."

The search on Thursday focused on a section of the nearby South Esk River.

A high water level meant plans to put police in kayaks to assist the search could not go ahead.

"We will reassess where we are at with this (search)," Insp Flude said.

"We are completely baffled, we've had no evidence (or) information come in that would lead us to believe Ben is anywhere apart from where we thought he was on the night he went missing and that's in the vicinity of the Perth area."

Searches by land, air and water have involved hundreds of people and entered more than a thousand properties.

Phone records show Mr Plowright's mobile did not leave the Perth area and police do not believe he has been the victim of crime.

Mr Plowright's family is holding up but preparing themselves for the worst, Insp Flude said.