A 12-year-old refugee who has made repeated suicide attempts on Nauru will die if she is not taken off the island, doctors have said in the latest of more than half a dozen warnings about her health to the Australian Border Force.

The girl is suffering from post-traumatic stress disorder and major depressive disorder. She is eating “almost nothing”, according to those caring for her, and has made multiple attempts to kill herself, including by setting herself on fire.

“If S does not receive treatment, her physical and mental health are very likely to continue [their] deterioration, with an ongoing high risk of suicide or death secondary to the consequences to dehydration or malnourishment,” the latest doctor’s report, filed on Tuesday, said.

“She should be moved to an appropriate child and adolescent inpatient facility at the earliest opportunity.”

Guardian Australia has chosen not to reveal the girl’s name, because she is a minor, instead referring to her by the initial S.

Over six consultations over the past six weeks, S’s mental state has deteriorated dramatically, with doctors repeatedly warning she was growing critically unwell.

“S’s condition has deteriorated to the extent that she needs admission to a child and adolescent inpatient facility which can manage both her physical and mental health by a multidisciplinary team. If her minimal food and fluid intake persists, she will need intravenous fluids and also nasogastric feeding. She will also require appropriate cultural and linguistic support. Unfortunately, there are no facilities of this nature on Nauru.”

S told a psychiatrist she believed suicide was “the only way to get out of here. Is better being dead than here.”

Her father asked a psychiatrist on the island whether S would recover if she were moved. “I told him that I believed she would be better but she would need psychological treatment to help her overcome the traumatic experiences she had been through.

“I also discussed with [him] about a safety plan and I emphasised the importance of locking up medications and hiding potential harmful objects.”

Staff on Nauru have confirmed S was being seen by the Australian government’s health provider, International Health and Medical Services, last month but its staff have since stopped visiting her at her family’s accommodation in Ewa, in the north of Nauru.

On Tuesday, S collapsed and was taken to Nauru hospital but was discharged within hours. The Australian government has told court hearings over other medical cases that Nauru hospital is unsafe for surgery or other complex interventions, and does not have a child psychiatrist.

The offshore regime on Nauru is being noticeably – but without announcement – emptied of the most seriously unwell refugees and asylum seekers.

About 20 people were moved off the island at the weekend but more than a dozen children who are refusing food and fluids remain there. No one was airlifted out during the last week’s Pacific Islands Forum out of concern, government sources say, that it would embarrass Nauru.

One refugee was even held on Nauru during the forum in defiance of a court order that she be immediately removed from the island. She has since been moved to Australia.

About 100 children remain on Nauru; most have been there more than five years. Doctors have recommended that more than half of them be moved off Nauru immediately because of serious and worsening health conditions that cannot be treated there.

The Australian Department of Home Affairs – which has ultimate authority over the offshore processing regime on Nauru and on Papua New Guinea’s Manus Island – has consistently declined to comment on individual cases.

Nauru’s government has rejected the findings of Australian courts, and statements from the UN, that children are unsafe in the country.

“Children of refugees and asylum seekers on Nauru have access to education, health services, welfare, good accommodation and a range of social services provided by the Nauru and Australian governments,” the government said. “Nauruan children grow up happy and healthy on our island. Activists [are] playing politics and distorting facts.

“To suggest any child is in danger just because they live in our country is offensive.”