The commonwealth government was warned about violent unrest at Manus Island detention centre weeks before deadly riots occurred but allegedly did nothing to stop it, a court has heard.
Iranian asylum seeker Reza Berati died and 77 others were injured in three days of riots at the detention centre from February 16 to 18, 2014.
Former Manus Island security guard Chandra Osborne has brought Supreme Court action against the federal government and security firm G4S, alleging they were warned about increasing violence but still put her at risk.
Her barrister Tim Tobin said G4S wrote to then-border protection minister Scott Morrison on February 6, 2014, warning about a deterioration in detainee behaviour.
Mr Morrison was informed the centre had "very limited security infrastructure, which currently created a significant and real risk for safety and security", Mr Tobin told the court in Melbourne on Monday.
He alleged this was one of many repeated warnings the government and G4S were given about rising violence at the centre.
G4S guards filed reports about large rocks being used as weapons and umbrellas, bed posts and tent pegs being fashioned into shivs.
The centre was overcrowded and security infrastructure was limited, with issues including lack of secure fencing, lighting and CCTV.
"In the weeks leading up to the riots, the defendants knew that there had been protests and incidents of unrest by detainees, including violence and using makeshift weapons," Mr Tobin said.
"They knew the unrest was caused partly by uncertainty about the prospects of detainees settling in Australia, and knew basic security infrastructure was not in place."
In an ABC interview played to the court, Mr Morrison said the riots were anticipated and the government took steps to increase security at the facility in the weeks beforehand.
Mr Tobin disputed this and said there was no evidence any steps were taken in the six months prior to protect staff from the riots or to stop them from occurring.
During the riots he said "blood and violence permeated throughout" with semi-automatic rifles and shotguns fired, rocks thrown, property damaged, fences and gates pushed down.
Some G4S staff were trapped under a fence and attacked with rocks and clubs, but he said none had access to personal protective equipment.
Ms Osborne is one of 20 security guards alleging the federal government and G4S failed to provide a safe workplace at the detention centre.
She has suffered serious psychiatric injuries, including ongoing trauma and depression, as a result of the riots and unsafe working environment, Mr Tobin said.
Ms Osborne claims she is partially incapacitated for employment due to her injuries and is seeking compensation for loss of earnings.
Multiple witnesses, including several other Manus Island security guards, will give evidence as the trial continues before Justice Andrea Tsalamandris.
The Commonwealth will give its opening remarks on Tuesday.