Pressure is mounting on the Tasmanian Government to stop logging native forests inhabited by swift parrots after the Federal Government reclassified the species as "critically endangered".

Scientists at the Australian National University put the case for the upgraded listing to Environment Minister Greg Hunt, who confirmed it yesterday.

It came after Forestry Tasmania failed to gain Forestry Stewardship Council (FSC) certification, in part due to concerns over a lack of protection for swift parrots in old-growth clear-felling areas.

The parrots only breed in Tasmania and it is estimated there are less than 2,000 left.

The bird was listed as "critically endangered" by the world's foremost authority on endangered species, International Union of Nature, last year.

Dr Dejan Stojanovic, who has devoted his career to researching the parrots, said according to modelling it was likely the species would be extinct within two decades.

"What we're seeing now is this already very reduced population being eaten away very slowly but surely by sugar gliders," he said.

"It's a really rapid rate of collapse."

He said there was a strong link between deforestation and the parrots' demise.

"That's why it's so important to focus on protecting what's left in Tasmania." the Australian National University scientist said.

Greens urge state reclassification

The Greens called on the Tasmanian Government to follow through with the reclassification at a state level.

Senator Nick McKim said the State Government should immediately ban the clear-felling of native forests, at the very least in swift parrot habitats in southern Tasmania.

"This beautiful little bird is becoming a casualty of the Liberals' ideological fixation with native forest logging, even though it requires massive subsidies from Tasmania's long-suffering taxpayers," he said.

Forestry Tasmania has suspended logging in swift parrot habitats on Bruny Island but environmental campaigners are calling for a permanent ban.

The State Government is still yet to release its protection plan for the threatened species, which is more than two years overdue.

Gutwein ignores calls to halt logging beyond Bruny

Forestry Minister Peter Gutwein said Tasmania was an active participant in the National Swift Parrot Recovery plan.

He ignored calls for the further scaling back or cessation of logging in swift parrot habitats in light of the reclassification.

"Logging has been halted on Bruny Island because it is one of a number of offshore islands where sugar gliders haven't been able to threaten swift parrot numbers and their habitat," Mr Gutwein said.

"An evidence-based swift parrot management plan is being prepared to better manage habitat."

Former Greens leader Bob Brown called on the Federal Government to recommend curtailing Forestry Tasmania's activities, to protect the parrot.

He said the bird's survival hinges on the Federal Government's recovery plan being updated with drastic measures.