More than 30 Australian women and children living in "appalling conditions" in a Syrian detention camp have launched court action to compel Canberra to bring them home.

Their case opened at the High Court in Melbourne on Tuesday, nearly a year after Australia repatriated the last group of four women and 13 children -- the wives, sons and daughters of the Daesh terrorist group fighters -- from Syria.

"The situation of the remaining persons detained is stark and dire," said Peter Morrissey, counsel for the charity Save the Children, which is acting on their behalf.

"Save the Children Australia represents women and children charged with no crime, detained in piteous and appalling conditions," he told the court.

"Their health, safety and dignity are seriously compromised by any standard. Their detention in the camps has endured for several years."

Save the Children is asking the court for a writ of habeas corpus (or unlawful detention), requiring the government to bring the 11 women and 20 children from Al Roj camp in Syria before the court in Australia.

Since the defeat of Daesh, the Al Roj camp has been under the control of the PKK/YPG, recognised as a terrorist group by Türkiye, the US and the European Union.

"Despite countless opportunities to repatriate these families, the Australian government has ultimately failed in its duty to bring all of its citizens home to safety," said Save the Children Australia chief executive Mat Tinkler.

"We desperately hope these children and their mothers will be imminently repatriated home to safety. It is unfathomable that the Australian government has abandoned its citizens," he said in a statement.

Repatriations of Australian women and children from Syrian camps are a politically contentious issue in a country long known for its hardline approach to immigration.

The Australian women and children have lived in the Al Hol and Al Roj detention camps in northeastern Syria since the 2019 collapse of the Daesh.