Labor has helped the government fast-track a bill to close a potential loophole in its offshore detention policy.
The Senate cleared most of its schedule on Thursday to urgently deal with the bill, before politicians head off on a lengthy winter break.
Its substance is the subject of challenge in three High Court proceedings.
Attorney-General George Brandis said the urgent treatment of the bill did not mean it wasn't considered legally solid.
"This government believes that the Act has a sound legal foundation," Senator Brandis told parliament on Thursday.
The bill enhances the government's statutory powers on regional processing agreements with other countries and "puts beyond doubt" its legal authority to implement the arrangements.
Australian Greens Senator Sarah Hanson-Young said one of the families involved in the legal battles had a young baby, born on Australian soil.
She accused the government of trying to strip the child of its time in court and urged the parliament to wait until the cases were concluded.
"What is so worrying about letting that baby have its day in court?" she asked the Senate.
Labor Senator Kim Carr reluctantly declared his support for the measures, despite the former government getting no help from the coalition when it tried to introduce regional processing in Malaysia.
"We will help this government out because we're better than them when it comes to these questions," he told the Senate.
However, Labor is concerned at the speed at which the bill was passed, having cleared the House of Representatives in an hour just one day earlier.
Independent Senator Jacqui Lambie echoed that concern, labelling the Labor-coalition agreement to fast-track the legislation "dangerous" and "rude".
She believes it's a "get out of jail free card" for the government.
The Greens failed to make several changes to the bill, including imposing mandatory reporting of abuse, journalist access to the centres and to limit detention to a maximum of three months.
The legislation comes after reports of sexual and physical abuse of women and children, and mental illness.
"More abuse, more torture, more children being driven to self harm, that's what's being allowed to happen in this parliament today," Greens Leader Richard Di Natale said.
