Hundreds of people have attended a rally in Tasmania's World Heritage Area (WHA), protesting against the Federal Government's push to have some forest delisted.

The Commonwealth has applied to the World Heritage Committee to have 74,000 hectares of forest taken off the register, saying much of it is degraded.

Greens Leader Christine Milne says the Government's claim that it is not worth of listing is simply untrue

"They are listed as World Heritage, they stand as World Heritage and we're going to keep them as World Heritage," she told the crowd.

Organised by the Bob Brown Foundation, speakers included Peg Putt from the group Markets for Change and Home and Away actress Lisa Gormley who made an emotional plea.

"Destroying this forest is destroying part of our humanity," she said.

Activist Miranda Gibson, who set a record for a tree-sit protest in the area, says the protesters will not give up.

"The only reason that these trees are still standing is because we came here and we put our bodies on the line and we made sure that the trees didn't fall."

The extension of the WHA boundary was part of the forestry peace deal which was brokered by industry and environmentalists over four years of talks.

The deal was designed to end conflict in the forests

The new Liberal Government plans to dismantle the deal when Parliament resumes next week.

A Federal Liberal MP accused green groups of being dishonest about the heritage values of the forests the Government wants to delist.

Eric Hutchinson says the Government's actions are justified because the forests have previously been logged.

"They just can't have it both ways," he said.

"They can't say that forests are going to be destroyed, and in the next breath say they are suitable for World Heritage listing.

"This is the hypocrisy of these people, they need a cause."

Senator Richard Colbeck says the anti-forestry protest will not deter the Government from the delisting plan.

"The Government made a commitment at the last Federal election to move to delist areas of forest that shouldn't have been listed in the first place," the Senator said.

"We've started that process and we intend to continue with it."