A new report, prepared for the Greens, recommends the Swift Parrot be reclassified as critically endangered as logging threatens their only known nesting habitat in southeast Tasmania.

Evidence suggests the bird's population, assumed at best to be 1,000 breeding pairs, has been in substantial decline since 2003.

They could be extinct within some decades if action wasn't taken to protect their habitat, Greens leader Bob Brown said.

"This is a story about a deliberated extinction of an amazing little Australian," Senator Brown told reporters in Canberra.

The Swift Parrot winters on mainland Australia, feeding on the blossoms of box woodlands from Toowoomba to Canberra and Adelaide, before flying to Tasmania in summer.

The Tasmanian Regional Forest Agreement negotiated between the commonwealth and Tasmanian state governments allowed the annual destruction of 1,000 hectares of the parrot's habitat, Senator Brown said.

"If you've got no nesting sites ... you've got no birds.

"It is not unlike the government-deliberated extinction of the Tasmanian tiger a century ago."

Senator Brown called on Mr Rudd to "move in and announce a dispute" under the forest agreement.

The commonwealth should withdraw from the agreement if Tasmania did not agree to protect the parrot's habitat.

"This is a case of extinction in front of our own eyes ... and it's got to stop."