A woman who gave birth to a baby on an international flight from Samoa to Auckland was remanded in custody after she appeared in court today - charged with abandoning the baby girl and assaulting her.

The 29-year-old Samoan woman's baby is now in the care of Child Youth and Family (CYF).

During her brief appearance at Manukau District Court today, the woman was granted name suppression, and was remanded in custody without plea until April 9 .

The woman was charged six days after cleaners found the baby in a toilet rubbish bin on a Pacific Blue flight from Samoa to Auckland.

She was on her way to New Zealand with 72 other passengers to work as a kiwifruit picker when her daughter was born. She also has one other child living in Samoa.

The infant was found after the woman had left the aircraft. The mother and baby were both taken to Middlemore Hospital in South Auckland.

Detective Inspector Mark Gutry said abandoning a child was a serious matter.

But whether or not the woman was sent back to Samoa would be a matter for the court and Immigration to decide, Mr Gutry added.

"We're working with Samoan authorities and authorities in New Zealand to ensure the best outcome.

"We have spoken to people on the plane, and certainly they've been able to provide us with information in relation to this matter.

"It's not certain when the mother went into labour, and nobody else was aware that she was in labour prior to the flight.

"What they've said and what they've told us is before the courts now," Mr Gutry said.

He added the baby was well and had not suffered significant injuries or long-term effects.

"We are asking that the mother stays in custody until her medical treatment is completed and her immigration issues are resolved.

"At this stage we don't expect there will be any further charges," Mr Gutry said.

Part of the police inquiry looked at where the child was born. It was discovered by staff after the plane had landed, and passengers had left.

Whether the child was treated as a New Zealand or a Samoan citizen had yet to be finally determined but she may be treated as Samoan, he said.

However, that did not indicate she was born over Samoan airspace or in Samoan territory, he said.

"There are a whole lot of issues around that - the aircraft and where that is from, where they have come from, where exactly she was born. So there are a whole lot of issues around that to be addressed."

That issue was not necessarily one the police would take up.

"The police concern is the welfare of the child and the offences that have been committed around the birth and the abandonment," he said.

Marion Heeney, regional director of Child, Youth and Family, said the mother has agreed to place the child temporarily in their care.

"The child will be placed with family in Auckland and we will continue to work closely with those involved to determine what long term arrangements are best for this baby," Ms Heeney said.

A spokeswoman from New Zealand Immigration said they would not comment on individual cases.