MORE than 120 scientists have appealed to federal Environment Minister Malcolm Turnbull not to approve Tasmania's pulp mill at its planned location until further research is carried out.

The 128 experts have sent a signed statement to Mr Turnbull calling for a fully integrated independent assessment of the $2 billion Gunns Ltd project in the Tamar Valley, north of Launceston.

One of the signatories, Dr Francisco Neira, a research scientist at the Tasmanian Aquaculture and Fisheries Institute, says a detailed study along the Tamar estuary should be undertaken for at least one year.

The scientists represent fields including chemistry, zoology, botany, oceanography, atmospheric science, marine biology and environmental impact assessment.

They say key issues were left unexplained when Gunns withdrew the project from scrutiny of the state's independent Resource Planning and Development Commission in March this year, citing delays and escalating costs.

Premier Paul Lennon reacted by introducing a fast-track assessment process of the mill through state parliament.

The project has now been approved by Tasmania's parliament, but still needs federal environmental approval.

Mr Turnbull has delayed his own decision until a federal report is compiled by Chief Scientist Jim Peacock into what possible effects the proposal could have on marine waters and migratory and threatened species.

The results could be known as early as this week.

The scientists are concerned over the mill's "dumping of 64,000 tonnes of effluent per day in the Bass Strait", its impact on forests for wood supply, and air pollution in the Tamar Valley.

Dr Neira said there were "serious concerns with the state's fast-track assessment".

"Gunns and the Tasmanian Government have failed to properly assess the impacts of the pulp mill's effluents on the marine environment and the Tamar estuary," Dr Neira said.

He said studies along the estuary's length should be carried out for at least one year "to ascertain what impacts the mill may have on this highly sensitive estuarine ecosystem".

Dr Neira said the Tamar estuary acted as a breeding and/or nursery ground for numerous fish species including anchovy, flathead, yellow-eyed mullet and Australian salmon.

He said atmospheric experts had expressed concerns over the mill's location in the Tamar Valley "whose well-known inversion layer can trap air pollution for days at a time".