The immigration department has confirmed that three Iranian asylum seekers have inflicted harm on themselves at Nauru's offshore processing centre.
An Iranian man attempted self-harm on Thursday, while another two Iranians did the same on Saturday, an Immigration Department spokesman told AAP.
No further details were available due to privacy reasons.
'Medical and mental health support is obviously available to all clients on that facility,' the spokesman said on Sunday.
Under the government's new offshore processing regime, 254 asylum seekers have been transferred to Nauru, while Papua New Guinea's Manus Island is expected to start receiving transfers in the coming weeks.
Greens immigration spokeswoman Sarah Hanson-Young said she wasn't surprised to hear people were committing self-harm on Nauru.
'This is exactly what experts said would happen,' she told reporters in Sydney, adding that similar incidents would happen again.
Refugee Action Coalition spokesman Ian Rintoul said Nauru's processing facility lacked adequate resources to deal with mental health problems.
'The government has created the circumstances in which it must have known that there would be a very high level of anxiety and mental illness created by what they're doing,' he told AAP.
A number of detainees held a protest at the Nauru centre on Sunday, calling on authorities to immediately process their asylum claims, Mr Rintoul said.
Meanwhile, two security guards at Sydney's Villawood detention centre have stood down as Australian Federal Police (AFP) investigate an alleged assault on a detainee.
An AFP spokesman said CCTV footage was being reviewed as part of an investigation into an incident earlier this month.
'It was an alleged assault and it was referred to us on October 3,' the spokesman said.
In other news, two suspected asylum seeker boats with more than 150 people on board were intercepted by Australian authorities on Saturday.
ACV Hervey Bay intercepted a vessel with 49 people northwest of Cocos (Keeling) Islands, while HMAS Bundaberg intercepted another boat with 104 passengers off Christmas Island.
Authorities will transfer the 153 passengers to Christmas Island.
Opposition immigration spokesman Scott Morrison said Labor's 'half-hearted' policies had created a chaotic situation that people smugglers continued to exploit.
'While Labor remains in denial about reinstating the full suite of coalition measures to stop the boats, record boat arrivals continue,' he said in a statement.
'Sri Lankan arrivals also keep coming, with Labor refusing to enter talks with the Sri Lankan government to send back their nationals before they enter our waters.'