Forest protesters in Tasmania no longer have the potential of a huge fine hanging over their heads after the state's workplace safety regulator lifted a ban on their activities.

Key points: A notice effectively banning protests by the Bob Brown Foundation has been withdrawn by Tasmania's work health and safety regulator

A notice effectively banning protests by the Bob Brown Foundation has been withdrawn by Tasmania's work health and safety regulator A Hobart magistrate described the notice as "unjustifiably wide"

A Hobart magistrate described the notice as "unjustifiably wide" The regulator will now "reconsider" the issue

The Bob Brown Foundation received a notice from the state's workplace safety regulator last week, threatening fines of up to $500,000 if alleged unsafe activities by protesters didn't stop.

It came after protesters rallied in the state's north-west to stop the state government-owned Sustainable Timbers Tasmania from harvesting trees in an area of the Tarkine.

An appeal against the notice by the Bob Brown Foundation was dropped on Wednesday after the regulator withdrew it in the Hobart Magistrates Court.

Lawyers for the regulator conceded they were in a "quandary" about how to define "unsafe" activity. ( Supplied: Bob Brown Foundation )

Legal representation for the state's regulator, Sarah Kay, conceded the grounds of the notice were too wide.

"The regulator has expressed a willingness to reconsider," Ms Kay told the court.

When asked how unsafe "activity" was defined, Ms Kay told the court, "We're in a bit of a quandary in that regard".

"I think the prohibition notice is unjustifiably wide," Deputy Chief Magistrate Michael Daly told the court in response.

Speaking outside court, lawyer for the Bob Brown Foundation Roland Browne said it was the outcome they were hoping for.

Bob Brown Foundation lawyer Roland Browne expects the regulator will draw up another notice. ( ABC News: Phoebe Hosier )

"The Magistrate has set aside the prohibition notice, that is it no longer applies and the appeal was successful with the agreement of the workplace regulator," Mr Browne said.

"The Bob Brown Foundation has been protesting across Tasmania for a long time, we hold rallies, its part of our existence and we're not going to be stopped by a notice that's invalid that tries to interfere with the rights we have to protest about forest operations in Tasmania.

"Next time the regulator wants to try and use work health and safety to stop protests in Tasmania. he's going to have to think twice about it and confine himself to the law.

"The constitution applies to everyone, including the state of Tasmania and its administrators.

"When they [the regulator] go to draw up another notice — and we expect they will — it needs to comply with the law and the constitution," Mr Browne said.

The decision didn't come without more than an hour of dense legal argument.

Questions were raised as to whether Magistrate Daly had the jurisdiction to hear the complaint, given the fact it involved citizens' constitutional rights to political communication, which are typically heard in the High Court.

Magistrate Daly told the court it was an unusual way for court proceedings of this kind to start.

"Usually, sensible people have sensible discussions and then a prohibition notice is issued," Magistrate Daly said.

The Hobart courtroom was full of both pro-timber advocates and supporters of the Bob Brown Foundation.

Upon leaving court, a supporter of the timber industry told Mr Browne, "It's not over yet".