The two-year state and federal government sponsored peace process broke down in October, with environment groups saying they failed in a dispute over the amount of sawlogs to be cut from native forests.

Since then discussions resumed informally, and now a new agreement between green groups and industry is said to be close.

The biggest surviving native timber processor, Ta Ann Tasmania, says it is deeply concerned about the viability of its two veneer mills without an agreement.

Sources close to the negotiators described the talks as at another "critical stage" on Wednesday.

Of an original claim to protect 572,000 hectares of high-conservation value Tasmanian forests, environment groups are understood to have reduced their bid to a total of about 525,000 hectares.

Tasmanian Premier Lara Giddings told reporters the state cabinet was ready to meet at short notice, with legislated backing needed to release around $100 million in federal assistance for Tasmania.

"We are yet to receive information either way saying there is agreement or not," Ms Giddings said.

"In preparation for hopefully signing that agreement, an emergency cabinet meeting was planned," she said. "I have now deferred that until we get appropriate information from the signatories one way or the other."

The Tasmanian lower house is due to rise on Thursday. "We have one day left in the House of Assembly to debate an agreement," Ms Giddings added.

Prime Minister Julia Gillard last year offered a $276 million industry assistance package that would have ended most native forest logging.

Ta Ann was offered a 265,000 cubic-metre veneer quota but is again under pressure in the talks as it battles renewed environmental pressure over the source of its wood supply.

Former Greens leader Bob Brown this week joined the board of lobby group Markets for Change, which has taken its anti-logging campaign to Ta Ann's Japanese customers.

A new deal could cut the native-forest sawlog quota substantially below the 155,000 cubic metre-benchmark set in the Gillard agreement.