In a soon-to-be-published book about the country's environmental impact assessments, University of Tasmania law lecturer Michael Stokes says the parliamentary approval was questionable because an independent expert report by Sweco Pic was incomplete.

Mr Stokes said yesterday that he had spent 15 months investigating various legal aspects of the approval, which was rushed through by former Premier Paul Lennon after Gunns withdrew from the independent Resource Planning and Development Commission assessment.

"Under the Pulp Mill Assessment Act, the consultant had to report that the mill could proceed and Parliament had to vote on its approval but it seems to me we didn't have a proper recommendation from the consultant," Mr Stokes said.

"If you look at Sweco Pic's assessment, they are quite open about the fact that they didn't assess against all of the criteria."

Gunns labelled Mr Stokes's findings "ridiculous".

Mr Bartlett said the Solicitor- General gave advice on the matter before the vote and he did not believe there was any legal confusion.

"I tell you what, we need that pulp mill now, we need the jobs it will bring, we need the investment it will bring," Mr Bartlett said.

"My message to (Gunns) today is to get on with it."

Opposition Leader Will Hodgman also reiterated the Liberal Party's support for the project.

"We want to see this project get up and running, not a continued stream of internal naval-gazing," Mr Hodgman said.

Greens leader Nick McKim said Mr Stokes's findings sent a clear message that the project was fraught with danger, but the party would not be taking court action to prevent construction.

Wilderness Society campaign director Vica Bayley said Mr Stokes's legal view added to the uncertainty surrounding the project.

Australian Greens leader Bob Brown said building the mill "would not only be environmentally irresponsible and socially unpopular, it would clearly be illegal".

Gunns managing director John Gay is understood to be overseas as the company battles to find a joint venture equity partner before the end of next month.