Senator Brown said it had been a difficult decision to go public with his financial position but that he was "deeply moved" by the public response.

The veteran environmentalist and former Whitlam government minister, Tom Uren, has offered $1000, saying although he did not support the Greens he believed "men and women of goodwill, irrespective of their politics, should subscribe to make sure Bob Brown is retained in the national Parliament so that democracy can function".

Mr Uren said that he was "disturbed that a government agency controlled by a Labor government is going to try and bankrupt him".

The businessman Dick Smith has been in touch with Senator Brown's lawyers although it is understood he has not yet offered any money.

Mr Smith said pursuit of the threat to recover $239,000 in legal costs would rebound seriously on the state agency. "The damage they would do to themselves would be far greater than anything they can get out of it," Mr Smith said.

Nevertheless, he said he had offered to do all he could to prevent the bankruptcy.

"I'm a capitalist, and I don't support everything Bob does - but we need him in the Senate."

The Prime Minister, Kevin Rudd, said he was "very distressed" to read about Senator Brown's position.

The bill comes from a case Senator Brown launched in 2006 in the Federal Court to claim that logging in Tasmania's Wielangta Forest threatened the endangered wedge-tailed eagle, the swift parrot and the Wielangta stag beetle.

The full bench of the Federal Court overturned the decision in November 2007 and ordered Senator Brown to pay costs.

He was refused permission by the High Court last year to attempt to appeal the decision.

Forestry Tasmania lawyers have threatened to push Senator Brown into bankruptcy if he does not pay by June 29. Senator Brown would be disqualified from continuing as a senator if he were to be declared bankrupt or insolvent.

A spokesman for Forestry Tasmania, Ken Jeffreys, said Senator Brown's declaration of the legal costs was a media stunt.

"We offered in the last 12 months to settle for around $200,000. That offer was rejected by Senator Brown's lawyers, who asked for $140,000," he said. "That wasn't acceptable to Forestry Tasmania so we had no choice [but to go] back to the Federal Court registrar and came back with a certificate for $239,000."