The family is seeking compensation as well as aggravated damages, arguing the boy’s future earning capacity was “destroyed, or at least severely compromised”, while they continued to face out-of-pocket medical expenses. Originally from Iran, the boy and his mother travelled by boat in October 2013 to Christmas Island, where they were detained. A few days later they were sent to the Pacific island of Nauru. The Australian-funded asylum seeker processing centre on Nauru. In a series of agreements between Australia and Nauru from 2012 onwards, Australia arranged to send asylum seekers to a processing centre on the island. Management responsibilities were shared by both governments. The alleged sexual assaults took place over a period of about six weeks in late 2014. The assaults were allegedly committed by an older teenage boy, also a detainee, and were reported to centre officials and Nauruan police who investigated but did not press charges, Ms Ioannou said.

“These [sexual assault] cases are important in seeking clarity in the law for people who have been harmed,” Ms Ioannou said. “They are important in seeking to ensure incidents like these do not happen again.” The controversial Nauru detention centre. Credit:Angela Wylie Much of the claim filed in the Victorian Supreme Court this week concerned the contracting arrangements between the Commonwealth, Transfield and Wilson. Transfield had agreed in its contract to provide services “broadly comparable” with those available in Australia and to “establish processes to prevent detainees being subjected to illegal and antisocial behaviour”, the claim said.

Transfield in turn set the training of Wilson security officers, specified staffing numbers and removed personnel found to have acted inappropriately. The government appointed a contract administrator to help oversee the running of the centre. Lawyers for the boy argue the Australian government owed a “non-delegable” duty of care to him and that while Transfield was liable for failings by Wilson, the Commonwealth was liable for those of Transfield. Each of the three lacked proper systems to ensure sexual assaults among the population were prevented, monitored or responded to, while staff were not given enough training, the claim said. Each of the Commonwealth and the companies “knew or ought to have known” that a failure to take reasonable care of the boy’s safety “would expose him to a not insignificant risk of being raped or sexually assaulted by other detainees.”

The centre compound was surrounded by fences and locked gates and patrolled by guards. No one was allowed to leave without permission. Both Wilson and Broadspectrum, the new Transfield entity, chose not to re-tender for their Nauru contracts, which ended in late 2017. A Wilson spokesperson said the company was not yet aware of the legal claim, “although if the matter is now before the Supreme Court we will not be providing any further public comment.” Broadspectrum did not respond to questions. Home Affairs has been approached for comment. Fewer than 10 children remained on Nauru, Prime Minister Scott Morrison said on December 6 as he signalled the number would fall toward the end of the year.

"All the children that have had medical-related issues for transfers have been transferred," Mr Morrison said. But the government resisted a bill backed by the crossbench, Labor and the Greens that would have simplified approvals for medical transfers from Nauru and Manus islands. The government was accused of running down the clock in Parliament’s last session of the year to avoid becoming the first government to lose a vote on legislation in the House of Representatives since 1929. Mr Morrison said the proposals would weaken border security.