In a recent submission to the draft amendment bill, the group - made up of members from the Gilbert + Tobin Centre of Public Law and the UNSW Centre for Crime, Law and Justice - say provisions of it "remain in breach" of the implied freedom of communication in the Australian constitution.

The High Court found the existing laws "burdened" that freedom in 2016 after a challenge by former Australian Greens leader Bob Brown - one of only nine people ever charged under them.

The government was ordered to pay costs of more than $355,000.

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One author of the submission has also suggested the government look past long-standing tradition and release their advice around the bill's constitutional validity to ensure parliament can be "properly informed" when a final bill is brought forward.

The submission joins four others from the five-week public consultation period - including those from Community Legal Centres Tasmania, constitutional law expert Dr Brendan Gogarty, lawyer and Independent Nelson candidate Richard Griggs and Unions Tasmania - which have criticised both the scope and intent of the laws.

It states though the bill would largely remove the explicit reference to protesters, its operation would continue to affect their actions more so than other groups.

"In practice, and given the history of on-site protests in Tasmania, the burden created by the offences ... will still almost exclusively fall on on-site political protests that are targeted at legislative or regulatory change," the submission says.

Even if the constitutional validity can be addressed, the submission outlines a list of items which create offences and provide police powers that "extend beyond the legitimate limits of the criminal law in a liberal democracy".

Concern was raised around an element which reverses the burden of proof to require anyone charged under the act to define what constitutes a business space, and a failure to exclude protest activities allowed with a permit under the Police Offences Act.

The Community Legal Centres Tasmania submission suggested even people in opposition to the kunanyi/Mount Wellington cable car who attended a recent non-violent direct-action training session could be caught up under the laws.

"It flies in the face of fundamental, longstanding criminal law principals," said Professor Gabrielle Appleby - one of the authors of the UNSW submission - of the burden of proof changes.

"If parliament is asked to act ... it should do so with what the government knows about constitutional validity," she added.

More on the state government's anti-protest law changes

In his submission, Dr Gogarty urged the government to extent public consultation and release further information and legal advice to inform "meaningful" public input. Both Professor Appleby and Mr Griggs say there are precedents for the government to do so.

On Saturday, a government spokesperson said they had carefully considered the High Court's decision in amending the legislation and assured protests that do not impede lawful business activities and workers will not be affected by it.

"Legal advice to the government is privileged, and it is a longstanding practice that such advice is not released," the spokesperson added.

"The people of Tasmania have twice elected the Hodgman government with this policy, which protects the lawful right of businesses to operate and workers to do their jobs without disruption."

Last week, Labor joined calls for the government to extend public consultation.

Greens Leader Cassy O'Connor also urged the release of legal advice, but said: "If [the government] won't listen to the High Court, it's unlikely they'll listen to anyone".

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