A woman who secretly gave birth on a flight from Samoa to New Zealand may face criminal charges, police said Friday, as they investigated reports she abandoned her baby alive in the plane's bathroom.

Police are inquiring into "the alleged ... abandonment of the child by the mother" after the flight landed in New Zealand on Thursday, police communications manager Ana-Mari Gates-Bowey said. "A likelihood of this investigation is a criminal prosecution."

Media reports said the mother left the baby in a bathroom waste bin on the Pacific Blue plane carrying 150 passengers; others said she was spotted with bloodied clothes in an immigration line. Police have declined comment on the reports.

Gates-Bowey said late Thursday the woman had undergone surgery at Auckland's Middlemore Hospital and was later reunited with her baby. Its gender has not been disclosed.

"We are relieved to have been informed that both mother and child are reunited, are well and are now being looked after in hospital," Pacific Blue said in a statement Thursday.

The 30-year-old woman, believed to be a Samoan national, got off the aircraft at Auckland International airport early Thursday without flight attendants knowing she had given birth.

Immigration officials are investigating what information the woman provided on her visa application and how she boarded the airplane at such an advanced stage of pregnancy, spokesman Rowan Saker said.