Thousands of Australians have taken part in a rally on Saturday (22 October) in a gesture to show they welcome refugees and immigrants to the country, amid growing criticism against the alleged treatment of refugees by Prime Minister Malcolm Turnbull's government.

Over 20,000 people took part in the rally, including eminent political leaders, in around 25 cities across the country, in an attempt to encourage the government to take an empathetic approach towards accepting refugees and those seeking asylum.

"Events like this are incredibly important, especially when you celebrate and go out in the thousands to welcome refugees and people seeking asylum," Mohammad Al-Khafaji from Welcome to Australia, an advocacy group, told Reuters.

"They feel like they've been marginalised, been targeted by these far-right radical movements. They just don't want to participate anymore for fear of their lives," he added.

Jihad Dib, a Labour politician who took part in Saturday's rally from Sydney said that Australia was stronger with multiculturalism. "What we need to do is make sure every single person that wasn't here today is aware that our future is better when we walk together."

Australia has been heavily criticised by human rights groups for its harsh laws that are reportedly stopping the country from accepting immigrants.

Its off-shore detention centres — Nauru and Manus Island — have had growing complaints for allegedly "torturing" and harassing asylum seekers. There have been reports of sexual assaults on women and children too from the detention centres.

Under Australia's immigration policy, refugees who try to enter the country by sea are sent to the off-shore camp for processing as they are not eligible to directly enter the country.

People hold placards at a protest against the Nauru detention centre outside an immigration office in Sydney Getty

The massive rally has come within a week of Amnesty International releasing a report that highlighted the state of affairs on Nauru. It said that the conditions in which the 400 Australia-bound asylum seekers were held in the detention centre "amount to torture".

The report titled Island of Despair alleged that asylum seekers on Nauru are being driven to attempt suicide to escape from what the rights group described as the "prison-like" conditions they face in "indefinite detention", Reuters reported.

However, the Australian prime minister has denied the claims by Amnesty calling it a false report. He said his government is "compassionate and strong".