Private forest growers have used a parliamentary inquiry to raise concerns about Tasmania's forest peace deal.
Upper House MPs are holding a public inquiry into the peace deal legislation.
Australian Forest Growers chief executive Warwick Ragg says the bill is not in the best interests of all Tasmanians.
He says the durability arrangements are ineffective and will not stop damaging market campaigns.
"The provisions of durability, whilst highly commendable, do not seem to provide sufficient insurance against a meltdown of environmental support in the short or medium term," he said.
Conservationists claim the bill will not deliver peace in the state's forests.
Tasmanian Conservation Trust director Peter McGlone has told the hearing the bill is flawed and needs amendments.
"The TFA Bill and the Tasmanian Forests Agreement, if implemented unchanged, will not deliver a comprehensive forest conservation outcome, peace in the community or...also peace in the marketplace," he said.
Federal Environment Minister Tony Burke has returned to Hobart.
It is understood he is here for further meetings with Legislative Councillors.