A man who says his dog died during an overnight trip on the Spirit of Tasmania ferry is calling for an overhaul of the conditions animals are held in during the 12-hour crossing of Bass Strait.

Key points: Marcus Lehmann said he was not notified that his dog had been struggling

Marcus Lehmann said he was not notified that his dog had been struggling He believes conditions need to change for animal welfare during the 12-hour crossing

He believes conditions need to change for animal welfare during the 12-hour crossing A spokesperson for the Spirit of Tasmania said the company was in "direct contact" with Mr Lehmann

South Australian Marcus Lehmann took his "best mate" Mook on the Spirit of Tasmania as part of a permanent move to the state.

But he claims the 93-kilogram South African mastiff died during the 12-hour journey.

Pets are required to travel in the ferry's kennels and owners are not allowed to access the kennels during sailing.

Loading

Mr Lehmann said he was told that staff noted the 14-month-old dog was struggling earlier in the night.

"At 8:30pm it was noted [by crew] he was struggling, and I was not notified and at 11:00pm he was deceased," he said.

Mr Lehmann said he was informed of the dog's death when the ferry docked in Devonport the next morning.

"I think he suffocated, he had skin off his nose, off his head, off his feet, he tried really hard to save himself. It was horrific.

"They wrapped him in the sheet, threw him in the back [of Mr Lehmann's vehicle], said sorry, and let me go.

"This is Australia, this is Tasmania with my dead dog."

Mr Lehmann said he was "absolutely devastated" by the turn of events.

"The captain and the security guards were shocked as well," he said.

A spokesman for the TT-Line, which owns the Spirit of Tasmania ferry, would not confirm or deny the dog died on the ferry, but the company released a statement which said: "The Spirit of Tasmania is in direct contact with the owner of the animal, and has been since the incident was first reported".

Mr Lehmann said conditions needed to change for animal welfare during the 12-hour Bass Strait crossing.

"They need to have been in an air-conditioned area, and they need to have somebody watching them 24/7," he said.

"I would guess they're not allowed to have staff down there for any length of time because it kills [people], and then they go and put your bloody pets down there."

Marcus Lehmann said his dog Mooka Nhimu Andamooka was an "amazing, beautiful animal". ( Supplied: Marcus Lehmann )

Mr Lehmann said his dog always made an impact on people.

"He got photographed by two of their workers on the way in because he was such a massive, magnificent animal," he said.

Tasmanian Premier Will Hodgman said matters like this needed to be investigated, and he expected an investigation would occur.

"We'll get an appropriate inquiry into these matters by appropriate authorities to deal with this as quickly as we're able," he said.

A year ago, 16 polo ponies were found dead in the back of a truck after being transported on the same route.

Those deaths are the subject of court action in Victoria.