Tensions flared and scuffles broke out in Federation Square, forcing mounted police and those on the ground to form barricades to separate the angry crowds.
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Reclaim Australia protesters took the geographical higher ground in one of a number of Australia-wide protests opposing "sharia law, halal tax and Islamisation".
Reclaim Australia are a group pushing nationwide rallies against "sharia law, halal tax and Islamisation".
Protesters holding anti-Muslim placards are seen at a Reclaim Australia Rally at Martin Place in Sydney on Saturday, April 4, 2015. (AAP Image/Mick Tsikas) NO ARCHIVING
Anti-racist protesters and other groups oppose their viewpoints.
Police presence at Sydney rallies
A heavy police presence has managed to keep any clashes at bay in Sydney where anti-racist and anti-Islam groups have turned out.
On either end of Martin Place, separated by a wall of police, anti-racist and anti-Islam protesters have faced off near the scene of last year's Lindt Cafe siege.
On the lower end braving the rain on Saturday were vocal supporters of Reclaim Australia, a group pushing nationwide rallies against "sharia law, halal tax and Islamisation".
Many of the flag-waving crowd-goers, in the hundreds, chanted "Aussie, Aussie, Aussie - Oi, Oi, Oi" and were carrying home-made banners denouncing sharia law.
But it was a proposition those in the anti-racist rally corner labelled absurd.
"There is no possibility of sharia law in Australia, that is absolutely ridiculous," Tony Iltis said.
Mr Iltis was part of a smaller but passionate crowd that slammed Reclaim Australia's "racist" slant.
"Basically they are neo-nazis who are able to not look like neo-nazis because the mainstream has become so racist," Mr Iltis said.
"I think the Muslim community needs to know that not all Australians are racist. I think they feel intimidated and how the Jews felt in the 1930s."
Anti-racist and anti-Islam protesters have faced off in Sydney, separated by a wall of police. (AAP)
Tensions almost erupted when a woman ran on stage at the Reclaim Australia camp, grabbed the microphone and told the crowd they should be ashamed.
Riot police were quick to respond and quell any clashes.
Among the Reclaim Australia crowd, many sporting Australiana memorabilia, was Greg and his home-made sign that compared sharia law to pedophilia.
"I'm just standing up for our freedom of speech and way of life," he said, wearing a green and gold shirt.
Rally organisers deny Reclaim Australia is racist, but say protesters have a problem with Islamic extremists who want to live by sharia law.
Event organiser Sarah Spearpoint says, like her, moderate Muslims also don't accept extreme views of their religion.
Pauline Hanson attends rally
One Nation leader Pauline Hanson has declared she is not a racist during a rally against Islam in Brisbane.
Ms Hanson, who narrowly lost her fight for a seat in the 2015 Queensland election, joined hundreds of protesters in King George Square.
Many were draped in the Australian flag and carried signs denouncing sharia law and halal certification for Australian products.
One Nation leader Pauline Hanson speaks at a rally against Islam in Brisbane. (AAP)
The group Reclaim Australia is holding nationwide rallies against "sharia law, halal tax and Islamisation".
But the rally was not an exercise in racism, Ms Hanson said.
"We have people here today who stand against racism. Thank you for your support," she said.
"So do I."
Ms Hanson said she and her supporters had endured trial by media and those with hidden agendas.
"Let my fellow Australians judge me on what I say. Don't deny me the right to have our say," she said.
"I am not a racist. Criticism is not racism."
Ms Hanson said she was merely a proud Australian fighting for the country's democracy, culture and way of life.
Tempers flared as a counter-rally was held opposite the event and at least 30 police officers kept the two groups separate.
"Go home bigots, go home," members of the counter-rally chanted.
But Reclaim Australia speaker David Truman said their opponents were using tired and untrue slogans.
"They hate free speech. They use fascist tactics to try and shut it down," he said.
"I've got news for you and for them - we are not racists or supremacists of any kind."
