The April 2006 document was sent from the consultant to Gunns and raised problems with the site selection assessment.

However, Gunns said yesterday the pulp mill had gone through approvals at state and federal levels, including consideration of the site.

The letter said there was very little documented evidence to meet the Resource, Planning and Development Commission guidelines.

"The assessment process undertaken by Gunns falls well short of the guideline requirements and assessment which would typically be undertaken for such a project," it said.

"By tampering or attempting to enhance that process you run a serious risk of jeopardising the validity of the site selection and consequently threatening the project approvals."

The consultant's name was blacked out in the document, along with identifying references to their company.

Bass Greens MHA Kim Booth said it was more evidence Gunns had manipulated the assessment process, and then pulled out when it became clear it was going to fail the RPDC guidelines.

Mr Booth has moved a motion - to be debated today - calling for the Pulp Mill Assessment Act to be repealed because a number of risk areas had not been properly assessed.

The consultant's letter said they had been instructed not to use certain methodologies in assessing the best site - between Longreach and Hampshire near Burnie.

The letter also said information was collected from the Department of Primary Industries, Water and the Environment, but was not used in the assessment.

"Whilst the outcomes may not be what you want (the consultants are) protecting Gunns' interests by presenting the most defendable outcome from the data available," it said.

A spokesman for Gunns said the mill had been approved through federal and state permits.

"The site selection process included a detailed assessment of social, environmental and economic factors," he said.