Three people are in hospital after being hit by a lawnmower on a busy Launceston street.

Police say a registered Launceston City Council lawnmower driven by an employee hit a group of youths on Wellington Street about 9am.

Three people were taken to the Launceston General Hospital with minor injuries.

Investigations into the crash are underway and the council has been contacted for comment.

In the state's south, police are concerned about a man seen leaping close to cliffs at Blackmans Bay this morning.

They say the man was seen about 7am, dancing near the blowhole holding a pole with ribbons attached.

A land and sea search failed to find him.