Qatar expressed regret on Wednesday after women on 10 flights were forced to endure invasive physical examinations, and announced an investigation that an informed source said could lead to criminal prosecutions.

Australia branded Qatar's actions as "appalling" after 13 citizens on one of the flights, a Sydney-bound Qatar Airways service, were subjected to vaginal inspections when a newborn baby was found abandoned in the airport.

In its first account of events, Qatar said the baby girl was wrapped in plastic and left to die in a bathroom rubbish bin, prompting what sources said was a lockdown of the airport.

Women were then led from aircraft to ambulances on the tarmac where they were subject to cervical examinations to see if they had recently given birth.

A source briefed on the official investigation into the October 2 incident said those involved in the invasive checks could be prosecuted.

But Australia continued to pile pressure on Qatar, with Foreign Minister Marise Payne announcing that the scale of the incident went beyond a single flight.

She told a Senate committee that women on "10 aircraft in total" had been subject to the searches, including 18 women on flight QR 908 to Sydney -- 13 of whom were Australian.

AFP understands one French woman on the Sydney-bound plane was also among them, while diplomatic sources suggested women from other countries were affected.

Payne, who has described the incident as "grossly disturbing" and "offensive", did not specify where the other flights were heading.

Australian Prime Minister Scott Morrison also weighed in on the controversy on Wednesday, describing the treatment of the women as "appalling" and "unacceptable".

"As a father of a daughter, I could only shudder at the thought that anyone would, Australian or otherwise, would be subjected to that," he said.

The UK foreign ministry said in a statement that it was "providing ongoing support for two British women following an incident in Doha".

"We have formally expressed our concern with the Qatari authorities and Qatar Airways, and are seeking assurances an unacceptable incident like this cannot happen again," it said.

The incident may upend Qatar's efforts to boost its reputation before it  hosts the soccer world cup in 2022
The incident may upend Qatar's efforts to boost its reputation before it hosts the soccer world cup in 2022 AFP / PASCAL PAVANI

Qatar is an ultra-conservative Muslim monarchy, where sex and childbirth outside of marriage are punishable by jail.

Ahead of the 2022 World Cup, it has struggled to reassure critics that its promises on women's rights, labour relations and democracy are credible.

Facing potentially devastating commercial and reputational damage, Qatar vowed to guarantee the future "safety, security and comfort" of passengers.

"While the aim of the urgently decided search was to prevent the perpetrators of the horrible crime from escaping, the State of Qatar regrets any distress or infringement on the personal freedoms of any traveller caused by this action," Qatar said in a statement.

Prime Minister Sheikh Khalid bin Khalifa bin Abdulaziz Al-Thani had ordered an investigation and the results would be shared with international partners, it added.

The Qatari statement, a rare act of contrition for an authoritarian Gulf state, did not explicitly say that women had been forcibly examined, referring only to a "search for the parents".

A source briefed on the investigation told AFP the inquiry would seek to determine what laws might have been broken, any individuals responsible and recommend disciplinary action or prosecutions if warranted.

The newborn had been "concealed" in a plastic bag and buried under rubbish in a bathroom bin, according to the Qatari account.

"The baby girl was rescued from what appeared to be a shocking and appalling attempt to kill her. The infant is now safe under medical care in Doha," it said.

Human Rights Watch called Wednesday for the airport incident to spark action to protect women.

"In Qatar and across the Gulf region, sexual relations outside of wedlock are criminalised, meaning a pregnant woman who is not married, even if the pregnancy is the result of rape, may end up facing arrest and prosecution," the watchdog said in a statement.

"Qatar should prohibit forced gynaecological exams and... also decriminalise sex outside of wedlock."