An Australian doctor has been brought to tears by the abuse and trauma he witnessed in Nauru's immigration detention centre.
Paediatrician Dr David Isaacs is one of several doctors, workers and guards turned whistleblowers exposing what they say is a culture of cover up, rape, self harm and abuse on Nauru, in defiance of laws that could land them in prison. 
"I saw a six-year-old girl who tried to hang herself with a fence tie and had marks around her neck. I've never seen a child self-harm of that age before," Dr Isaacs told ABC's 7.30.
"After five days, I went home and had nightmares. I didn't expect that.
"I didn't expect to be so, um, traumatised by these people's trauma. These are people, ordinary people and we're treating them with, um - sorry, we're treating them with incredible cruelty," he said, clearly shaken and upset.
"It's child abuse. Putting children in detention is child abuse. So, our Government is abusing children in our name," he said.
Alanna Mycock, a nurse who worked with Dr Isaacs on Nauru recounted the confronting ordeal of a mother in detention.
"We'd seen that she'd been raped there. She was offered more time in the showers for sexual favours," she said.
7.30 also aired hidden camera footage of detention centre guards joking about shooting a detainee.
Detention centre operators Transfield and Wilson Security have told the Senate inquiry investigating allegations of abuse that staff are trained to report abuse, including through a special hotline. 
But a whistleblower told the program that he was never told about the hotline.
The Senate inquiry is expected to demand children be removed from detention as part of its key recommendations, according to 7.30.
The inquiry is also expected to recommend mandatory reporting of sexual abuse, and for the Immigration Department and Federal Police to conduct a full audit of all allegations.