Shares in Broadspectrum, the company which runs Australia's asylum seeker detention centres in the Pacific, have been placed in a trading halt.
In a letter to the Australian stock exchange, the company asked for trading to be halted following the Papua New Guinea government's announcement that it will close the detention centre on Manus Island.
The company requested the halt until Friday, and will make a statement about the likely impact of the PNG Supreme Court ruling that the centre is unconstitutional.
Broadspectrum, formerly known as Transfield Services, recently had its contract to operate Manus and Nauru extended by 12 months.
It is among the bidders for a new five-year deal with Australia's immigration department.