The United Nations has urged the Australian government to release a Tamil family-of-four from detention on Christmas Island while they continue to fight deportation from Australia.

Carina Ford, a lawyer acting on behalf of the family, received a letter from the UN Human Rights Committee on Wednesday advising them that the committee had approved their request for interim measures and asked the government to release the family within 30 days.

"The committee ... has requested the State party to transfer [the family] within 30 days into a community setting arrangement or to find another way to end their existing situation of detention," the letter, seen by SBS News, read.

AAP

Sri Lankan parents Priya and Nadesalingam and their Australian-born daughters Kopika, four, and Tharunicaa, two, are being held in immigration detention while their case for asylum is before the Federal Court.

An application was made to the Human Rights Committee on September 27 under the Optional Protocol to the International Covenant on Civil and Political Rights on behalf of Tharunicaa.

Family friend Angela Fredericks told SBS News she was feeling "very relieved" by the UN's decision.

"We know detention is no place for children and for families, so I feel relieved that on an international level this family's situation is being watched," she said.

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"I would ask our government to comply and find a solution to ultimately let this family come back to Biloela where they need to be."

Members of the small Queensland community of Biloela - where the family lived prior to its detention - have long been vocal in support of the family, who they say made a valuable contribution to the rural town.

Home Affairs Minister Peter Dutton's office has previously confirmed the family would not be returning to mainland Australia while their case is being determined.

Late last month, Tamil Refugee Council spokesman Aran Mylvaganam said the family had been told by Border Force officials to "learn to adjust" to Christmas Island.

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The family are the only people detained on Christmas Island after they were removed from the Melbourne immigration detention centre, where they had lived since March 2018, last month.

The court case will hear Tharunicaa's application for a protection visa and is expected to take months to finalise.

Despite being born in Australia, Tharunicaa has been deemed an "unauthorised maritime arrival" under the Migration Act, which stipulates children of asylum seekers who arrive in the country by boat cannot apply for a visa.

A Home Affairs spokesperson says the Department "is aware an interim measures request has been issued by UNHCR," maintaining the family is "residing on Christmas Island and will remain there whilst the judicial review proceedings are before the court."