It is notoriously hard and expensive to travel on the north- bound Devonport-to-Melbourne ferries from April to June, and southbound ones from September to November.

TT-Line chief executive Charles Griplas said yesterday that the state-owned business was working on a campaign to entice those in caravans, motor homes and campervans to travel outside the peak periods.

"I don't want to give out too many details, but it will be similar to the Tassie Escape specials we had for caravans," he said.

"Those using motorhomes and caravans are creatures of habit. They love in the winter period to go up north and in summer go south, so you're really trying to break that habit and stop people from all travelling in that one week."

The Campervan and Motorhome Club of Australia's Don Mackrill said it would be tough to convince the sun- seekers.

He thinks the main disincentive of using the ferries is the cost, and wants the Commonwealth to close the gap between what a traveller spends to get to Tasmania via ship and the equivalent distance via road.

The cost of 164,613 vehicle crossings was subsidised last financial year under the federal Bass Strait Passenger Vehicle Equalisation Scheme.

A spokesman for federal Infrastructure Minister Anthony Albanese said there were no plans to review that scheme.