A group of seven activists has filed a constitutional challenge to Queensland legislation that outlaws the phrases "from the river to the sea" and "globalise the intifada" when used in a way that makes a member of the public feel menaced, harassed or offended.
The activists formally launched the High Court challenge at a rally outside Queensland Parliament House on Tuesday.
Marque Lawyers managing partner Michael Bradley, who is representing the group, said the case goes to the heart of constitutional protections for political speech.
"We're asking the High Court to declare Queensland's prohibited expressions law invalid on the basis that they infringe the constitution," he said.
Mr Bradley said the constitution guaranteed freedom for everyone to communicate with each other on government and political matters.
"This law is a massive overreach. It's the first time that an Australian government has made a law that criminalises specific words," he said.
The group claims neither slogan has a fixed, inherently anti-Semitic, racist or violent meaning.
Mr Bradley said the outcome could have national implications as other states contemplated similar legislation.
"We know, for example, the NSW government has been considering a similar law, so that would stop them in their tracks," he said.
Justice for Palestine Magan-djin spokeswoman Remah Naji told the rally the case was about both Palestine and fundamental democratic rights in Australia.
"This is about a genocide and our right to protest genocide, and to demand that this government uphold its obligation under international law," she said.
More than 20 people have been charged under the laws since they took effect in March, with offences carrying a maximum penalty of two years' jail.
The laws were introduced amid tensions over the Israel-Gaza conflict and target expressions the state government and many Jewish organisations regard as anti-Semitic.
Both phrases have been widely used at pro-Palestinian rallies, with supporters insisting they are political slogans about Palestinian liberation and critics saying they amount to calls for violence and the destruction of Israel.
Ms Naji said the ban singled out Palestinians and their supporters.
"These phrases, especially 'from the river to the sea', this is part of our history," she said.
"This is part of our advocacy for Palestinians, so it specifically targets the Palestinian community."
Deputy Premier Jarrod Bleijie has said the laws were needed to push back against "venomous, poisonous rhetoric" and to ensure people felt safe in public spaces.
Jewish groups have backed the crackdown, saying the chants have fuelled fear and anxiety in the community.
A hearing date for the High Court challenge has yet to be set.
