Rumney MLC Tony Mulder will table an amendment to restore the guaranteed wood supply to the 155,000 cubic metres originally agreed to by state and federal government in the intergovernmental agreement signed in 2011.

After negotiations stalled last year, the forestry industry agreed to a compromise further and accepted the lower amount of 137,000 cubic metres a year.

"I think they have gone beyond their remit," Mr Mulder said.

The change proposed by Mr Mulder are just two of a raft of amendments being prepared by MLCs, despite warnings from signatories to the deal not to interfere.

MLCs will debate the controversial legislation to enact the forestry peace agreement next week.

Altering the wood supply cannot be done without impacting on the amount of forests able to be reserved, effectively killing the deal.

Mr Mulder also wants to make permanent protection for forests dependent on securing Forest Stewardship Council certification for the native logging industry.

The agreement states environment groups will "actively support" FSC certification for remaining logging, seen as a key to restoring overseas markets for Tasmanian wood products.

Mr Mulder said there was still a risk the Forest Stewardship Council would not grant certification.

- ROSEMARY BOLGER