THE case against the Abbott government's potential handover of 153 Sri Lankan asylum seekers, believed to be Tamils, to the authorities they were fleeing will be heard in the High Court on Friday.
The decision to hear the case followed an injunction on the potential hand-back filed by refugee advocates with the court on Monday.
An initial directions hearing via video conference in Melbourne was held on Tuesday, where Justice Susan Crennan agreed for the full bench to hear it "expeditiously".
The case will be heard after the government gave the court an undertaking it would not hand those on board the vessel back to authorities for 72 hours, pending the Court's decision.
It comes after Immigration minister Scott Morrison on Monday confirmed more than 40 Sri Lankans were handed back to Sri Lankan authorities in a separate transfer on the high seas.
That process, which he said in a statement involved an "enhanced screening process", has been questioned by refugee advocates and political critics alike.
That first vessel was reported more than a week ago, but was not confirmed by government until Monday, while the existing of a second vessel carrying 153 asylum seekers was confirmed in Court on Tuesday.
Acting for Minister Morrison, Solicitor-General Justin Gleeson QC confirmed the second vessel did exist and that Australian officers had intercepted the boat and those on board.
Those on board that boat could be a "refoulement", or breach, of Australia's obligation not to return refugees to authorities they were fleeing if they would be in danger.
While the return was slowed due to the case being filed and an injunction imposed on such actions by Justice Crennan on Monday night, the government in court promised not to return them until the case was heard.
The hearing came as Leader of the Government in the Senate Eric Abetz said he was not sure what fate lay in wait for those already returned to Sri Lanka.
But he said it was his understanding that when returned, they are taken to police for interviews and could potential be jailed, as it was an offence to leave without government approval.
His comments came after Prime Minister Tony Abbott last week described Sri Lanka as a "nation at peace", despite questions remaining about the treatment of those already returned.