Australian Greens Leader Christine Milne describes a Coalition push to curb the activities of conservation groups in the marketplace as an attack on free speech.

The Federal Government has flagged changes to consumer laws to make it harder for lobby groups to campaign against companies in the marketplace.

Groups like Get Up! and Tasmanian-based Markets for Change are currently exempt from a section of the Consumer and Competition Act which prevents action to hinder a third person buying goods from another.

The Federal Government wants to curtail such activities because they are damaging legitimate businesses.

Tasmanian Liberal MP Eric Hutchinson says the Government is considering reviewing how the Act relates to environmental groups.

"These people are running orchestrated campaigns that are well-funded and it is reasonable that they are obliged to have the same consequences as corporate organisations when they make misrepresentations in markets particularly," he said.

Greens Leader Christine Milne says the move is a disgrace.

"Markets need to be informed," she said.

The Tasmanian Greens leader describes also described is a threat to free speech.

Nick McKim says conservationists should have the right to launch market-based campaigns.

"To say that they're somehow going to face punitive punishment for having a view and sharing that view in the international markets is quite draconian," Mr McKim said.

"It's an attack on freedom of speech and an ideologically-driven attack on the environment movement...no-one should be banned from having a say.

"I think it's a sign of things to come from the Abbott government and I think it will also be a sign of things to come if we end up with a (Tasmanian) Liberal majority government at the next election."

'We won't be gagged'

The group Markets for Change says it will not be gagged.

The group investigates and exposes companies which is accuses of driving environmental destruction.

Spokeswoman Peg Putt, a former Greens MP, says she believes the public wants the information it provides.

"I think that consumers these days want to know about the environmental origin of what they're buying and make a choice that's informed and that's best for the planet," Ms Putt said.

"I intend to keep on giving them the information to help them be able to do that."

Ms Putt says information the group provided to Japanese customers about Ta Ann timber products was important.

"The markets understood it was eco-wood then were told by us that actually it came from high conservation forest and we showed them the supply chain," she said.

"At which point it was Ta Ann who had to answer difficult questions when they couldn't, they were told they had to lift its game so it could sell into those markets again."

Industry calls action 'sabotage'

Colin McCulloch from the Forest Contractors Association says legislative change is needed.

"Its something we've been looking for many years as a part of being at the forefront of disputes and having our workplace continually disrupted and having it flow through to market sabotage," he said.

Mr McCulloch agrees with the Liberals description of the environmental activity as economic sabotage, saying the moment for free speech has "well passed."

Tasmanian Opposition spokesman Matthew Groom says groups like Markets for Change have been undermining legitimate forest businesses in Tasmania for too long.

"If you go out and make misleading statements and you're damaging commercial interests as consequence of it, you should be held to account for it," he said.

"It doesn't deny people telling the truth about things, but what we've seen in this state is protest groups go out and mislead the public."

The Federal Government will review the entire Act.