Australia on Thursday accused asylum seekers held in Pacific detention camps of falsely reporting sexual assault in order to get sent to Australia, a day after a newspaper published leaked documents detailing abuse at the Nauru immigration centre.

More than 2,000 incidents, including sexual abuse, assault and attempted self-harm, were reported over two years at the Australian-funded Nauru detention centre, more than half involving children, Guardian Australia reported.

Immigration Minister Peter Dutton on Thursday said asylum seekers were lying about sexual abuse and repeated comments he made earlier this year that refugee advocates were encouraging detainees to self-harm and set themselves on fire.

"I have been made aware of some incidents that have reported false allegations of sexual assault, because in the end, people have paid money to people smugglers and they want to come to our country," Dutton said in an interview on Australian radio.

"Some people have even gone to the extent of self-harming and people have self-immolated in an effort to get to Australia. Certainly some have made false allegations."

Under its hardline immigration policy, asylum seekers intercepted trying to reach Australia by boat are sent for processing to Australian-funded camps on Nauru, which holds about 500 people, and on Manus island in Papua New Guinea. They are told they will never be settled in Australia.

The harsh conditions and reports of systemic child abuse at the camps have drawn wide criticism at home and abroad. Australia, however, has vowed there will be no change to the policy, which has been pursued by successive governments.

Australia says the policy is needed to stop asylum seekers dying at sea on the dangerous boat journey from Indonesia to Australia. Hundreds of people died attempting the trip in the years before the policy was put in place.

Refugee advocates said the leaked reports show the urgent need to end Australia's offshore detention policy and that asylum seekers must be given medical and psychological support.

Hayley Ballinger, a child protection worker at the Nauru detention centre from 2014-15, said that it was an "absolute insult" to suggest that refugees had lied about abuse that has now been widely documented.

"All of the statements speak for themselves. Certainly the clients I saw there suffered and they really suffered. And this stuff really, really did happen. We witnessed it first-hand," Ballinger told Reuters.