Friends and family of a Tamil family are putting pressure on airlines to refuse to deport them on behalf of the Australian government.

Asylum seekers Priya and Nadesalingam and their two Australian-born daughters could be deported at any moment after exhausting their final legal avenue.

AAP

An application for an assessment of the dangers that toddler Tharunicaa may face if she is sent to Sri Lanka was blocked by the Department of Home Affairs this week.

The family remains in a Melbourne detention centre where they have been held since March 2018 when they were taken from the tiny Queensland town of Biloela.

In a last-ditch bid to stop them leaving Australia, their supporters are now urging airlines, including Qantas, Virgin and Sri Lankan Airlines to refuse to participate in the family's deportation.

"An act of courageous leadership would be for airlines to commit to only flying this family home to safety in Biloela," friend Angela Fredericks told SBS News.

SBS News

"We are calling on the whole aviation industry - from those responsible for the management of the airlines, down to the pilots, ground crew and cabin crew, to show moral leadership and refuse to fly Nades, Priya, Kopika and Tharunicaa from Australia to an uncertain fate in Sri Lanka."

Ms Fredericks said the family have "grave fears about their future if they are forced back to Sri Lanka".

A petition to bring the family home to Biloela has been signed by more than 200,000 people.

The Department of Home Affairs previously told SBS News it would not be making further comment on the case.

"This family's case has been assessed, over many years, by the department and various merits review bodies. These decisions have also been the subject of judicial review applications in the courts," a spokesperson said.

Qantas, Virgin Australia respond

In a statement, Qantas and Virgin Australia said they do not operate flights between Australia and Sri Lanka.

"Virgin Australia works with a number of government organisations to transport passengers for a range of reasons and complies with Australian Immigration Law," a spokesperson said.

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Qantas added: "These are very complex and emotive matters but it’s not for airlines to adjudicate on who should and shouldn’t get to stay in Australia after the government and courts have made their decisions."

Last year, six US airlines announced their refusal to participate in transporting children who have been separated from their families at US borders under Trump’s immigration policies.