The federal government has announced a further inquiry into children in detention on Nauru, investigating reports of abuse and sexual misconduct by staff against children. It will also look into allegations charity workers have coached children in making complaints and even in self-harm.

The immigration minister, Scott Morrison, confirmed 10 employees of Save the Children, a non-government organisation contracted to provide welfare, education and protection for children on Nauru, had been told to leave the island.

Morrison has appointed former integrity commissioner and acting department head Philip Moss to head the wide-ranging inquiry investigating “all of these matters”.

“The matters that have been brought to my attention are concerning, certainly the allegations of sexual misconduct are abhorrent and I would be horrified to think that things of that nature have taken place,” Morrison said.

But he said suggestions staff on the island were assisting protests and encouraging detainees to hurt themselves in an effort to undermine the policy of offshore detention “were also very serious”.

Moss will investigate “the orchestration of protest activity and the facilitation of that protest activity on Nauru, including the tactical use of children in those protests, to frustrate the ability of those working in the centre”.

The 10 staff members told to leave Nauru are not alleged to have engaged in misconduct against children, but are accused of encouraging protests, complaints of abuse and even of coaching self-harm.

The chief executive of Save The Children, Paul Ronalds, rejected the minister’s allegations and said the governmement had not provided his organisation with any evidence of staff wrongdoing before the claim was leaked to the media, or since.

Nor had it received the report cited by Morrison.

“We reject in the strongest possible terms these allegations that our staff have in any way fabricated stories of abuse or in any way encouraged self-harm,” Ronalds told a media conference on Friday. “The truth is that cases of child self-harm are a reality, and have been well-documented.”

Ronalds said the recent spate of self-harm incidents, which have included children stitching their lips shut, had been sparked by the government’s announcement that it would reintroduce temporary protection visas, but not for asylum seekers on Nauru.

“Our staff have responded to these very distressing incidents with professionalism and compassion,” Ronalds said.

Five Save The Children staff were suspended in August over allegations they had supported a detainee protest by giving a “thumbs up” sign to demonstrators.

“In that case, all of the allegations against Save the Children staff were found to be unsubstantiated, and all of the staff returned to full duties,” Ronalds said.

Save the Children said in an earlier statement instances of child self-harm were “a reality that has been well-documented”.

“The evidence is very clear to us: the long-term and prolonged detention of children has a devastating impact on the mental and physical well-being of children. This can no longer be denied.”

Morrison said he would be appalled if accusations of sexual abuse proved true, but that the fabrication of allegations to further a political agenda was also serious.

“The public don’t want to be played for mugs, they don’t want these allegations being used as some sort of political tactic.”

Guardian Australia has published extensive evidence of child abuse and instances of self-harm on Nauru, including:

Australian federal police confirmed to Guardian Australia it had received a referral from the Department of Immigration and Border Protection. It had not started an investigation.

Greens senator Sarah Hanson-Young, who this week publicly raised allegations of sexual abuse of detainees, said she did not believe staff on Nauru were encouraging protests or self-harm.

“The people who are being pushed to the desperation of self-harm are being pushed there by Mr Morrison’s policies,” Hanson-Young told reporters.

Labor immigration spokesman Richard Marles said there were “serious questions” about how the leaked intelligence reports containing allegations against Save the Children staff had made its way to the press without being shared with Save the Children managers.



“This is a disgrace. It is profoundly hypocritical of the minister,” Marles told reporters in Sydney.

“If the investigation of Mr Moss is to have any credibility at all then it must involve an investigation of the minister’s office about the handling of this information.”

When asked by Guardian Australia if the Labor party believed the Nauru detention centre was an appropriate place to detain children, Marles responded:

“It is important that Nauru is run in a way that provides, safe, dignified and humane accommodation to the people within the facility. We do have concerns about this. It is absolutely critical that the government gets on top of this so that it does provide accommodation of that kind.”

He added: “Nauru and Manus and Manus island both play very important roles in saving lives at sea. Labor is committed to offshore processing in an important strategy to ensure people do not lose their lives at sea.”

AAP reports that the opposition leader, Bill Shorten, says the government must be transparent in its inquiry into reports aid workers coached asylum seekers on Nauru to self-harm.



Shorten supported the inquiry but said on Saturday: “These are disturbing reports ... but I would just say to the government, ‘If you want to have community confidence in the way you are handling immigration matters, you need to be transparent and open.’ ”