Immigration Minister Peter Dutton has defended the quality of hospital medical services for pregnant women in asylum seeker detention on Nauru.

Key points: Condition of asylum seeker who gave birth prematurely on Nauru is slowly improving in a Brisbane hospital, the ABC understands

Condition of asylum seeker who gave birth prematurely on Nauru is slowly improving in a Brisbane hospital, the ABC understands Greens senator Sarah Hanson-Young says the mother should have been brought to Australia long ago

Greens senator Sarah Hanson-Young says the mother should have been brought to Australia long ago Prime Minister Malcolm Turnbull would not comment on the case

His comments come as a Somali refugee remains in a Brisbane hospital after she and her newborn son were medically evacuated from Nauru in a critical condition.

Ian Rintoul, from the Refugee Action Collective, said 22-year-old Naima Ahmed was 32 weeks pregnant when she underwent a caesarean section operation on Thursday.

The ABC understands Ms Ahmed has been taken off life support and her condition is slowly improving.

Mr Dutton said on Saturday there were "significant numbers of medical staff" on Nauru who provided care to asylum seekers in detention.

He said Australia's policy was firm on not allowing people in offshore detention into Australia, except in an emergency.

"This woman was provided with the medical support that you would expect," he said.

"There was $11 million of taxpayers money spent to upgrade the medical facility [on Nauru].

"Now the arrangement has been if people can't receive the medical attention that they require that they go to Port Moresby International Hospital.

"If the medical services are not available there, people are bought to Australia."

Prime Minister Malcolm Turnbull was also questioned about Ms Ahmed's condition, but said he would not comment on individual cases.

"Can I just say to you that every support in terms of health including medical support and mental health is provided to the people who are currently living in Nauru," Mr Turnbull said.

This was preventable: Greens

Greens senator Sarah Hanson-Young said the young mother now in hospital in Brisbane should have been brought to Australia long ago.

"Now, as a direct result of her forced isolation at the hands of the Government, she and her newborn baby are fighting for their lives," she said.

"It's important to recognise that this was preventable.

"Doctors said that choosing to keep women with complicated and dangerous pregnancies on Nauru, rather than bringing them to Australia, would result in tragedy.

"We should be closing the camps, assessing people's claims where they are and then flying those who need protection here safely."

'I had to give birth in worst place ever'

An Iranian woman who remains in detention on Nauru after giving birth at the local hospital has described a traumatic experience.

She spoke through a translator in a video provided to the ABC by the Refugee Action Collective.

Baby Rayan was born to an Iranian woman in detention on Nauru. ( Supplied: Ian Rintoul )

"I thought if I become refugee my conditions will get better, hospital conditions will get better," the woman said.

"But unfortunately it was worse. I had to give [birth] in worst place ever.

"There isn't any specialist in Nauru. There was just one midwife who was from Fiji... everywhere was dirty."

The woman burst into tears as she remembered her baby's birth.

"My baby was born with forceps. His heart rate was down. My husband was shouting and calling our (baby) son Rayan," she said.

"He said: 'Rayan please scream.' We thought he was dead. I had a very bad feel and I was dying.

"The doctor doesn't think my baby heart rate could be down and every second may we lose our poor baby."