The blaze was reported at 12.15am with three Tasmania Fire Service crews attending the scene on the Bass Highway at Sassafras.

Latrobe Police Sergeant Martin Parker said he was treating as suspicious the fire that destroyed Mr Rockliff's political billboard about 500 metres east of the ``Big Spud''.

Sergeant Parker asked anyone  with  information to contact the Latrobe Police Station or Crime Stoppers.

Mr Rockliff described the act as disappointing.

``My father and his mate went to the effort, putting the hayman up for something a bit different, for the enjoyment of people going past,'' the Liberal politician said.

``It's just disappointing that people have made a concerted effort to burn it down.''

Mr Rockliff said vandalism of political signs was unfortunately what politicians came to expect.

``All political parties have their signs defaced and vandalised.

``When it comes to the act of arson it takes it to another level.''

Mr Rockliff said he was going to erect several other ``haymen'' until the arson attack.

``I don't want to risk anyone else's properties,'' he said.

``People have agreed to have them up, but I'm not going to risk their property for my campaign.''