Parliament returns today to debate legislation to quash any legal threat to the pulp mill and extend the permits until 2017.

The legislation has prompted the Greens to move a no- confidence motion in the government and call for a referendum on the proposed legislation to be held at the same time as the state election on March 15.

As the lower house debates the pulp mill legislation, the Legislative Council may be forced to reconsider if the forestry peace deal is working given the vocal opposition to the pulp mill.

Hundreds are expected to rally against the pulp mill outside Parliament today.

Huon MLC Paul Harriss, who is standing as a Liberal candidate in the state election, said the protest showed the Tasmanian Forest Agreement had failed and he was considering invoking a clause that would effectively kill it off.

Under the legislation, either house of Parliament can vote to declare a failure of durability due to "substantial active protest" which, if successful, would block the creation of any new reserves.

The rally has been partly organised by the Wilderness Society, a signatory to the forest peace agreement, narrowly approved by the Legislative Council last year.

Mr Harriss said it was a clear breach of the environment group's obligations under the forestry peace legislation.

"The fact that there's this protest, in my view goes, right to the heart of durability," Mr Harriss said.

"My concern is where's the signatories? No one's condemning this protest," he said.

However, support for a pulp mill is not part of the forestry legislation and environment groups maintain they are free to oppose it.

Mr Harriss said the two were inextricably linked.

"Every one of them knows that it was the single starting point for the whole negotiation," Mr Harriss said.

Debate on the pulp mill legislation is expected to stretch into the early hours of tomorrow morning.

The legislation is set to pass with the support of the Liberals but the Greens have indicated they will attempt to delay a vote for as long as possible.

Greens leader Nick McKim confirmed yesterday they would move a no-confidence motion in the government before debate even starts.

"It's about whether we're going to lock into public subsidies for bulk undifferentiated commodity exports or whether we are going to move forward and continue the transition to create jobs and prosperity in those sectors where Tasmania has a competitive advantage," Mr McKim said.