Tasmania's premier announces financial aid for flood victims

Tasmanians who've lost homes and belongings in the state's worst floods in 40 years will be able to get immediate financial assistance, the government says.

Emergency aid of up to $750 per family, comprising $200 per adult and $100 per child, will be made available to help flood victims buy clothing, food, transport, shelter and personal items.

The Tasmanian government is also examining other support measurers and has officers on the ground supporting farmers with stock management.

"Our thoughts and prayers are with the families and friends of the three people missing - a man from Ouse, a woman from Latrobe and a man at Evandale - for whom police hold grave fears," Premier Will Hodgman said in a statement.

The Insurance Council of Australia has declared the event a catastrophe with at least 200 homes and businesses inundated, including 50 at Newstead, 35 at Latrobe, seven in Wynyard and five in Ouse.

Many others in outlying rural areas are also under water.

Authorities are warning people not to put themselves in danger to rescue stranded animals, as the search continues for an elderly Tasmanian man swept away by flood waters while feeding his sheep.

Tasmania Police say the 81-year-old man, named by the ABC as Trevor Foster, was swept into the rising Ouse River from his backyard following heavy rainfall.

"I want to reinforce that there should be no attempt by owners or members of the public to attempt to rescue those stranded animals," SES acting director Nick Wilson told ABC TV.

"You're simply putting yourself in danger - and certainly those lives of the responders."

Two other people remain missing in what the premier says are the state's worst floods for 40 years.

More than 100 people have now been rescued by helicopter across Tasmania.

The Spirit of Tasmania ferry service which runs between Melbourne and Devonport has been suspended until further notice because of the dangers posed by sunken vessels in the Mersey River.

Authorities are advising people to stay at home and not attempt to drive in flood-affected areas.

More than 100 roads are closed but some of the road-closure signs have been swept away.

Major flood warnings are current for five Tasmanian river systems.