About 900 men are housed at the Manus Island detention centre, off the coast of Papua New Guinea.
The man, who did not want to be named, said he ended up in hospital in Papua New Guinea after one round of abuse.
He said he was routinely placed into what is known as the Managed Accommodation Area (MAA) where he was assaulted by security guards.
“I was in the MAA for two weeks,” he said. “Guards throw me into this bed, took off my clothes, they put my hands in cuffs.
“I have naked body, I have bites from mosquito all over my body. The doctor who came to see me thought I had another disease, my body is so red from mosquito bites.”
The man said on one occasion, two Australian security guards and two Papua New Guinean guards punched and kicked him, and knelt on his back and shoulders.
“They are very criminal, security, nothing reported against them, they are doing very easy,” he said.
“I needed help, I said just leave me alone, I haven’t had nice treatment.”
He added there had been dozens of assaults by security guards on Manus Island in the time he had been there.
“They don’t like us, one of them told me go back where you come from, go back to your country,” he said.
The man’s claims come amid the release of a huge archive of files into the detention of asylum seekers on the Pacific island of Nauru.
The leaked files, published by The Guardian, detail the trauma and abuse inflicted on children held in detention.
The Refugee Action Coalition said claims of abuse must be thoroughly investigated by an independent organisation.
Spokesman Ian Rintoul said there had been routine use of solitary segregation in MAA in an attempt to break people.
“There is more than enough evidence now from Manus Island and from Nauru to get the inquiry that we really need,” he said.
“To get to the bottom of the kind of brutality and the kind of torture that is systematically used in offshore detention.”
Rintoul said the Federal Government would have footage of the alleged abuse carried out by security guards.
“There would be officers out there I’m sure that have got video footage,” he said.
Rintoul said Manus Island should have been shut down in April, when PNG’s Supreme Court ordered it be closed.
“The scale of human rights abuses that have been inflicted from when they were first unlawfully transferred, three years later those abuses are still being carried out,” he said.
- ABC