The rallies were planned in multiple locations around Australia today by Reclaim Australia, as well as counter-rallies opposing the group.
Reclaim Australia are a group pushing nationwide rallies against "sharia law, halal tax and Islamisation".
Anti-racist protesters and other groups oppose their viewpoints.
The tweets from the Reclaim Australia twitter account seemed innocent enough, at first.
Apparently no one at Reclaim Australia forsaw the potential for the stunt to backfire.
It quickly got weird.
However, it did not take long for Reclaim Australia to realise what was going on.
In a statement issued by Reclaim Australia shortly after the Twitter incident, spokeswoman Catherin Brennan apologised for the stray tweets.
"It has been brought to our attention that statements have been made on our official Twitter account that are not consistent with all our values," the statement read.
There were some suggestions this was all part of a hoax by what is a fake account not affiliated with Reclaim Australia. At the time of writing SBS had been unable to reach Reclaim Australia to verify the account's veracity.
"Over 20,000 Australians have been looking forward to the Reclaim Australia rally without incident and it is with a heavy heart that I must inform you that as a committee we have decided to postpone the 2015 Reclaim Australian event until further notice".
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
Rallies proceeded in a number of cities.
Victorian rally turns violent
Mounted police were forced to form a barrier between Reclaim Australia and counter protesters at opposing rallies in Melbourne.
Tensions among the crowds led to scuffles, with paramedics treating injured protestors.
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.
"We have people here today who stand against racism. Thank you for your support," Ms Hanson 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."
