The High Court in Australia granted a temporary reprieve on Sunday to the first group of asylum seekers due to be transferred to Malaysia under the government's swap deal.
The government had been preparing to send the first group of 16 asylum seekers to Malaysia at 11.30am on Monday.
But in a special hearing of the High Court on Sunday, Justice Kenneth Hayne ordered a temporary injunction, stopping their removal until at least 4:15pm on Monday.
Lawyer David Manne said the injunction gives the legal team time to argue that sending asylum seekers to Malaysia is unlawful.
The ABC reports Mr Manne's team represents 40 asylum seekers, including six minors, but the temporary injunction affects only 16 men who were set to leave for Malaysia.
Mr Manne says many of the asylum seekers are extremely fearful and distressed.
The injunction was issued on the same day that a boat with 50 asylum seekers on board was intercepted north-east of Christmas Island. It was the second to arrive since the Malaysia agreement came into effect.
Opposition immigration spokesman Scott Morrison said Sunday's arrival shows the government's Malaysian people swap deal is not working.