Mr Joyce will once again serve as deputy prime minister after defeating Michael McCormack in a Nationals leadership spill.

His return has thrilled supporters of the Murugappan family given his long-standing support for their campaign, something that puts him squarely at odds with Prime Minister Scott Morrison.

"He has been so supportive of this family for a very long time. I personally met with him when I visited Canberra two years ago," Murugappan family friend and supporter Angela Fredericks has told AAP.

"He has supported us. We are quite encouraged to know that we've got somebody who has taken the time to listen in such a great position."

Father Nades, mother Priya and Australian-born Tharnicaa and her sister, Kopika, have been locked up for more than three years while their fight against deportation has gone through the courts.

Mr Joyce has long said the family should be given a special exemption to remain in Australia because their two daughters were born here, and were Australians "as far as the community is concerned".

Just last week, he said the girls "didn't buy their tickets" and had a right to stay in Australia "despite what the allegations might be about their parents or their father".

The family was most recently detained on Christmas Island but were flown back to the mainland after Tharnicaa, 4, spent two weeks in hospital with a blood infection caused by untreated pneumonia.

They are now in community detention in Perth but Liberal Immigration Minister Alex Hawke has told them it is not a path way for permanent resettlement.

Prime Minister Scott Morrison has repeatedly said the family won't be allowed to stay.

A small but growing number of Liberal MPs have sided with the family, including Katie Allen, Trent Zimmerman, Jason Falinski and Ken O'Dowd.

The family wants to return to Biloela, in central Queensland, where they were living before their bridging visas expired and they were taken into detention in 2018.

Nades and Priya Murugappan have said they face persecution if they are deported to Sri Lanka. Both Tamils, they fled their homeland after the country's civil war and came separately by boat to Australia, having paid people smugglers.

They met after they arrived and are continuing legal battles to stay.

Nades has said that during the civil war he was forced to join the separatist Liberation Tigers of Tamil Eelam. He said he was harassed by the government after the army won the war and will be in danger if he goes home.

Priya said she and her entire family fled Sri Lanka for India after she watched her then-fiance and five other men from her village burned alive. She left that camp, bound for Australia, after deciding it was too dangerous to continue living there.

Australian Associated Press