A former guard who worked with Australia's juvenile detention centre in 2014 admitted during an inquiry that he had filmed himself asking teenaged inmates to perform oral sex on him. However, he claimed that his comments were "a joke".

"I was actually just going to say goodnight to them because I was leaving shift. I knew they'd take it as a joke, or I just assumed they would take it as a joke," Conan Zamolo, the guard at the Don Dale Youth Detention Centre said. He joined the centre in 2012 and stated that he had a good relationship with the inmates.

The admission from Zamolo came after a royal commission was set up to investigate the matter after an ABC show titled Four Corners, showed the inmates being allegedly meted out inhumane treatment at the juvenile detention centre.

Australian Prime Minister Malcolm Turnbull initiated a thorough inquiry into the incident "to get to the bottom of it, and expose what occurred and expose the culture that allowed it to occur and allowed it to remain unrevealed for so long".

He said at the time that he was "shocked and appalled" by the images that were telecast on the show.

The photos showed a teenager with his face covered being restrained to a wheelchair, which drew international criticism. The images also showed children as young as 10 being stripped naked, assaulted, tear-gassed and held in solitary confinement at the centre.

During the inquiry, Zamolo also admitted to asking another inmate to eat faeces and filming a boy urinating.

"At the time I didn't think it was inappropriate, but now I see how inappropriate it is," he admitted.

Australian child detention horror
A 17-year-old boy is shown bound to wheelchair at a juvenile detention facility in Alice Springs, AustraliaFrom Four Corners program by Australian Broadcasting Company

The Royal Commission into the Protection and Detention of Children in the Northern Territory is investigating the assault on the boys at Don Dale centre in Darwin, which took place between 2014 and 2015.