A woman who is in hospital on Christmas Island after attempting suicide was returned to the offshore detention centre against the advice of mental-health professionals after being transferred for treatment in Australia.

Fairfax Media has been told the women was transferred to Perth earlier this year but discharged from hospital and returned to detention before being sent back to Christmas Island against the advice. It is believed the woman, who is not a mother, tried to take her own life this week and remains in Christmas Island hospital.

Sources have told Fairfax Media there were several asylum seekers who continue to be held on Christmas Island despite advice that they be transferred to Australia for treatment for mental illnesses.

''This is not manipulation [of the system],'' a source said. ''It's widespread and it's getting worse.''

It comes as Christmas Island shire president Gordon Thompson said the number of women on suicide watch had increased from 11 on Wednesday, to 14 on Thursday.

''They are [on] constant watch,'' he said.

Immigration Minister Scott Morrison this week denied Fairfax Media reports that up to nine women had attempted suicide, saying multiple suicide attempts by women on Christmas Island were ''not correct''.

Mr Morrison has refused to provide information on self harm in detention, citing ''government commentary on such issues takes into account privacy and the impact public commentary may have in encouraging such behaviour''.

On Wednesday, Fairfax Media obtained advice from the Department of Immigration showing that, following a meeting on Christmas Island this week, there were ''seven individuals who made threats of self harm, four have actually self-harmed and one woman attempted suicide''.

But an International Health and Medical Service employee said the categories of ''self harm and ''attempted suicide'' were often hard to differentiate.

''A self harm could be a suicide attempt,'' the worker said.

The Royal Australian and New Zealand College of Psychiatrists said it was ''concerned but not surprised'' to hear of reports that women on Christmas Island were harming themselves.

''The college is extremely concerned that people are finding themselves in such a desperate situation that they are considering such measures as attempting suicide,'' said the president, Dr Murray Patton.

The government's leader in the Senate, Eric Abetz, described the incidents on Monday night as ''minor self harm''.

But Greens Senator and immigration spokeswoman Sarah Hanson-Young said that response was ''callous and insincere''.

''Suicide attempts are not 'minor incidents' as so ignorantly described by the Abbott government,'' she said.

''The Department of Immigration's own contract with Serco defines attempted serious self harm as a critical incident.''

Do you know more? Email swhyte@fairfaxmedia.com.au

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