Thousands of people protested in cities and towns across Australia on Sunday against the government's efforts to deport a Tamil family back to Sri Lanka, Gulf Times reported.

The asylum seeker family of four, including two children aged 4 and 2 born in Australia, are being held in a detention centre on remote Christmas Island while a last-minute appeal against their deportation is heard this week in a Melbourne court.

The parents say their family will face persecution as Tamils if they return to Sri Lanka. Greens leader Richard Di Natale accused the government of cruelty in deporting the family, who are supported by the community in the remote Queensland village of Biloela where they had lived for the past four years.

"This is senseless cruelty, this is cruelty for the sake of being cruel," Di Natale told a rally in Melbourne, the Australian Associated Press reported. Home Affairs Minister Peter Dutton has refused to budge despite mounting pressure from the community and opposition politicians to let the family stay.

Dutton said Friday that the parents arrived illegally by boat and successive courts had ruled the family did not qualify as refugees so they were "not owed protection" by Australia.

Priya, Nadesalingam and their Australian born children Kopika, 4, and Tharunicaa, 2, were at the centre of dramatic scenes on Friday when migration officials bundled them onto a midnight government flight from Melbourne to Sri Lanka. They were offloaded in the far-northern city of Darwin after a court granted an injunction against the deportation, but Saturday they were then flown to Christmas Island.

Speaking by phone to the national broadcaster ABC by phone from Christmas Island Sunday, Priya said they were all alone in the centre and the children were constantly crying. The family's lawyer, Carina Ford, said she understood they were the only inmates of the Christmas Island detention centre. She said keeping them behind bars so far away made it more difficult to present their case in a Melbourne court before the injunction ends on Wednesday.

The case centres on 2-year-old Tharunicaa, who has not been assessed for a protection visa.