Three government businesses contributed to the cost of full-page advertisements in the state's newspapers yesterday and today.

Launceston businessman John Pitt said on Wednesday that he had contacted more than 300 businesses statewide to get more than 100 organisations to sign an open letter calling for support for the Gunns project.

Mr Hodgman said while he agreed with the private businesses who wanted to see the pulp mill built, it was not appropriate for government businesses to get involved in a political debate.

Forestry Tasmania, Tasports and Tasrail were listed among those supporting the pulp mill.

Bass Greens MHA Kim Booth said the ad was clearly political and the government needed to ensure no government agency was involved.

Premier Lara Giddings said the shareholder ministers were not aware that the government businesses had helped pay for the ads.

She said she thought the organisers of the ads had done the right thing.

Ms Giddings said state- owned businesses had sought the advice of the government and had been told it was up to their boards and management.

She said each of the businesses contributed $200.

Launceston Chamber of Commerce executive officer Michael Bailey said that the chamber had not signed the open letter because its standing on the proposed pulp mill was already well known.

"We have not moved from our position to support it provided it meets the economic and environmental guidelines," Mr Bailey said.

TAP for a better Tasmania spokesman Bob McMahon said that Mr Pitt and his associates should consider Gunns' economic situation.

"They are hanging on for dear life so rushing to support this $2.3 billion project strikes me as utterly insane," Mr McMahon said.