Forestry Tasmania has offered an olive branch to the forest peace deal's environmental signatories, as they decide their position on major changes to the enacting legislation.

Both the state-owned company and fringe environmental groups delivered their final pleas on the eve of the amended bill returning to Parliament for consideration by the Lower House,

The forest peace deal, brokered by green groups, unionists and industry bodies in talks that lasted more than two years, involves protecting 500,000 hectares of forest from logging.

Two weeks ago, the Legislative Council backed potentially deal-breaking changes to the agreement, meaning only a small amount of forest would be reserved upfront

Forestry Tasmania has promised it will not log in areas proposed for protection under the agreement and its Chairman, Bob Annells, says he wants to make it clear that the company is committed to observing the spirit of the deal, not just the legislation.

"What we're saying today against the background of some of the suggestions I've heard in the media that we're looking to continue to log within World Heritage nominated areas, apart from the couple of coupes that we'll be finished in a matter of weeks, we will be out of those areas and we will stay out," he said.

The state-owned company is pleading with Lower House MPs to pass the revamped legislation, saying it has "zero chance" of achieving Forest Stewardship Certification without it.

At the same time, Tasmania's fringe environmental groups have revealed they will not stop protesting if the amended legislation becomes law.

They have labelled it a 'mutant' bill and have made a final plea to environmental signatories to reject it.

The Huon Valley Environment Centre's, Jenny Weber, says the legislation has been savagely attacked by the Legislative Council and will not achieve peace.

"We're calling this a mutant legislation, it's been savagely attacked by the Legislative Councillors for the interests of the forest industry and it will only entrench the continued logging of native forests," she said.

"There will be people who will continue to stand up for the defence of these ancient forests, these eco-systems that deserve immediate protection and are not guaranteed under this deal."

The Conservation Trust is urging the Greens to amend the peace deal legislation.

The trust's Peter McGlone believes the future of the agreement rests with the Greens.

"We think there is a possibility of rescuing this legislation if we actually get greater security over reservation and if we totally remove the quite absurd changes to the Forest Practices Act."

The Premier wants a response from signatories before the special sitting of the Lower House.

Political pressure

Premier Lara Giddings says the deal will fail if signatories reject the changes.

"The fact is we're waiting for the signatories to come back to us but we already have a piece of legislation now that has been amended in the Upper House," she said.

"It has been through a very difficult time through those amendments in the Upper House.

"We want to see those issues resolved, we believe that the core elements of the agreement are still there in place."

Opposition's forestry spokesman Peter Gutwein says the peace deal process is a sham.

"This Labor-Green government have abrogated their responsibility to an unelected group of people to make decisions about a publicly-owned asset," he said.

"That's simply not good enough and now we have a government that's paralysed by indecision, whilst it waits to hear from this unelected group as to what it should do.

"It's quite unbelievable that the Premier is waiting to hear back from an unelected group of people who've been meeting in secret about the future of her forestry legislation."