Prominent environmentalist Bob Brown has received legal advice his High Court challenge against the Tasmanian Government's anti-protest laws is free to proceed.

The former Greens leader was arrested under the laws while protesting at a forestry coupe in Lapoinya in January.

That gave him standing to issue a High Court challenge against the controversial legislation, on the grounds it contravened free speech implied in the Constitution.

The Director of Public Prosecutions (DPP) has now dropped the charges against Mr Brown.

"I've checked with my barristers ... they assure me that this case will proceed, because the case in the High Court is against the legislation, not a defence of me," Mr Brown said.

In a statement, Tasmania Police said it found Mr Brown was located on a "business premises" and therefore the charge relating to being in a "business access area" should not proceed.

Forestry Minister Peter Gutwein told 936 ABC Hobart the charges were dropped on a "technicality".

"We stand 100 per cent behind the laws and importantly the right for Tasmanians to got to work," he said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 30 seconds 30 s Bob Brown is arrested at a logging protest in Tasmania

Mr Brown said that showed the laws were too confusing for police to enforce.

"It's all to do with whether it's a business premise or access to premise — this is shoddy legislation," he said.

"It doesn't give police clear unquestionable direction."

Four others were arrested at the Lapoinya coupe under the laws.

They were among protesters who argued the section of native rainforest should not be clear-felled, given it is home to Tasmanian Devils and giant freshwater crayfish.

Tasmania Police said it was reviewing the cases of the others prosecuted.

Mr Brown said their charges should be dropped immediately.

"These are stirling Tasmanians trying to defend something precious in their neighbourhood," he said.

"They're never been on the wrong side of the law and they're very perplexed about the whole process."