The first person prosecuted under Tasmania's laws banning pro-life protests outside abortion clinics is appealing against his conviction.

Graham Preston is arguing Tasmania's Reproductive Health laws are unconstitutional and impinge both his right to freedom of religion and political speech.

It is a battle that may well end up in the High Court, with constitutional law experts saying Preston may have a point.

Tasmanian laws introduced in 2013 banned protests within 150 metres of a termination clinic.

Women seeking terminations argue the law is needed to protect their right not be harassed and vilified.

Pro-life supporters maintain their protests are protected by implied right to political freedom of speech in the Australian constitution and the guarantee of religious freedom in the Tasmanian constitution.

In July, Brisbane-based pro-lifer Graham Preston became the first to be convicted.

"We see this law in Tasmania as being a direct challenge to people being able to express their views and that's why we're challenging it," Preston said.

"Abortion is a political issue and on the day that I was arrested I was holding a sign that said 'Everyone has a right to life - Article Three Universal Declaration of Rights'," he said.

"I find it an incredible thing that a person can be arrested in Australia for promoting the Universal Declaration of Human Rights.

"We believe this creates a terrible precedent in Australia where you can have people forbidden to express view in public like this."

Preston is appealing his conviction, arguing the law is unconstitutional and constitutional law expert Michael Stokes said he might have a point.

"It has the potential to be a great case," Mr Stokes said.

"They're difficult issues and could easily see it go to the High Court and the High Court splitting on it.

"I don't think we'll get a unanimous decision from the High Court on this."

Tasmanian laws 'too broad'

Mr Stokes spoke to Tasmanian MPs before the laws were passed and expressed concerns they went too far in the interference with freedom of speech.

"I'm totally in support of laws which prevent harassment, intimidation, threats, all of that sort of thing but this goes beyond it," he said.

"The law was so broadly drafted, and one of my major complaints too, was that it extends to a protest on private land within the 150-metre radius.

"There is nothing which limits it to protest in a public place."

Issue of 'old and new rights'

While the abortion protest law has been the catalyst for the challenge, it is not the issue that the courts will have to consider.

It is a battle over the "old rights" of freedom of speech and religion versus the "new rights" not to be offended or vilified.

The right to religious freedom in the Tasmanian constitution can be repealed by the Parliament.

The Australian constitution can only be changed by the people by way of a referendum but because the right to political freedom of speech is only an implied right, it is up to the High Court to decide whether that right exists in modern Australia.

"That's going to be the issue ... are the old rights as important as they used to be thought to be, or should they give way to what we might call new rights not to be insulted," Mr Stokes said.

Preston's appeal against his conviction goes to Tasmania's Court of Appeal in October.