Rallies and counter-rallies have been held around the country, with one man arrested as opposing groups of protesters confronted each other over issues of extremism and tolerance.

The Reclaim Australia group said its rallies on Saturday were a public response to Islamic extremism and a protest against minority groups who want to change the Australian cultural identity.

The group held 16 rallies in capital cities, regional and rural centres, speaking out against sharia law, halal certification and Islamic extremism.

Counter-rallies organised by opposing groups were protesting against Reclaim Australia, which they say is anti-Muslim.

A man at the Reclaim Australia rally in Hobart was arrested and charged with assault after his group clashed with the counter-rally supporting multiculturalism.

Loading

Clare Fester, who organised the counter-rally in Sydney, said Reclaim Australia was racist and divisive.

"It's quite clearly an attack on Muslims and Muslim communities in this country," she said.

"It's all about halal food, sharia law, banning the burka.

"[It's] something I think that's been encouraged by mainstream politicians as well, with Abbott attacking Muslim leaders and telling them they need to stamp out extremism that really doesn't exist, certainly not in Australia."

Reclaim Australia's John Oliver said it was wrong to label the group racist.

"We're not against any particular race or any particular religion," he said.

"We're against the extremists of one particular religion.

"I know in Sydney and Melbourne they've got Muslims already signed on to attend because they can see what's happening and they don't like what's happening."

Heavy rain in Sydney did not deter either group, with 500 Reclaim Australia supporters gathering in Martin Place and police having to remove opposition protesters after they stormed the group's stage.

"We have an extreme ideology called Islam which is starting to gain a foothold in our societies," a man known as "the great Australian patriot" told supporters.

Anti-racist rally organiser Mel Gregson said Reclaim Australia was spreading "conspiracy theories", particularly by linking halal products with the Islamic State terrorist group.

Loading

"It's basically implicating good Muslim people in the political movements of a tiny minority," she said.

Ms Gregson said the coalition of community organisations, trade unions and left groups had chosen to hold their rally at Federation Square to directly oppose Reclaim Australia's message.

"We're not interested in holding our rally somewhere else and talking to people who already agree that racism is a bad thing — the vast majority of people in Australia agree with us on that," she said.

"What we're trying to say is that this is dangerous to allow hate speech to occur on the streets of Melbourne."

One Nation's Pauline Hanson addressed supporters in Brisbane, while opposition protesters booed and held signs saying "racists and bigots please go back to where you came from".

"My fellow Australians, we have people here today who stand against racism. Thank you for your support, so do I," Ms Hanson said.

"[The] media and some others have targeted this as a racist rally before any Australian has the opportunity to voice their concerns.

"For too long we have suffered trial by media and those with hidden agendas. Let my fellow Australians judge me on what I say, but don't deny me my right to have my say.

"I'm not a racist — criticism is not racism. I am a proud Australian fighting for our democracy, culture, and way of life.

"This rally being held across our nation today was called out of sheer frustration from ordinary Australians who fear for the future of our nation and the mindset of our politicians, who don't appear to be listening."

There was a significant police presence at the rallies in Brisbane's King George Square. ( ABC News: Alison Middleton )

Danny Nalliah from the Rise Up Australia Party addressed the rally in Melbourne and said he was "not against Muslim people, but ... opposed to the teachings of Islam".

"We love the Germans, we oppose the Nazi philosophy. We oppose communist philosophy but we love the Russians and Chinese," he said.

"Likewise, we oppose Islam but we love the Muslim people."

In Tasmania, the Reclaim Australia protesters were outnumbered by opposition groups, with 40 turning out to protest against halal products and Sharia law.

They were met by about 100 people in a counter-rally calling for an end to racism and Islamophobia.

Police kept a close eye on protests in Hobart's Franklin Square. ( ABC News: Linda Hunt )

There were several heated exchanges between groups, including pushing and shoving during the protest.

Likewise there was a heavy police presence in Adelaide as rival groups came face to face outside Parliament House in the city.

Hundreds of protesters rallied at Elder Park, then marched to nearby Parliament House carrying banners against Islam.

Some people were draped in Australian flags and some dressed as tubes of Vegemite.

Police cordoned off a rival group of supporters of multiculturalism, who protested against the Reclaim rally.

Protester John Bolton said his group was opposed to extremism but not Muslims in the wider community.

"What I'm not against is ordinary Australian people who happen to be Muslims who follow their faith, they don't need anybody's permission provided they comply with the Australian civil and criminal law and want to comply with our constitution," he said.

Police separate protesters from Reclaim Australia and the Socialist Party at opposing rallies in Perth, April 4, 2015. ( ABC News: Marcus Alborn )

About 300 people attended the rally at Parliament Place in Perth, including men, women and children.

Some of the men had their faces covered with skull masks or flags.

In their speeches, Reclaim Australia advocates denied several times that they were racist and said they just wanted Australia to be a Christian-based society.

Those at the rally goaded and jeered at a counter protest about one-third the size of the Reclaim rally.

Socialists, unionists and Indigenous people were joined by others who opposed the sentiments of Reclaim Australia.

A heavy police presence kept the two groups separated across the car park.