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 "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 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 incidents 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.