A Canadian woman has given birth aboard a plane to Tokyo after going into labour over the Pacific Ocean, an event the baby’s father described as “completely unexpected”.

The 23-year-old woman delivered a baby girl with the help of a doctor who volunteered after crew asked passengers for medical help, an Air Canada spokesman said.

The plane was given priority to land at Narita Airport, just outside the Japanese capital, but by the time it taxied to a halt, it had one more passenger than it had started with.

“I couldn’t imagine. This happened completely unexpectedly,” the father, whose name was not revealed, told Japanese television.

“It turned out to be a beautiful baby girl,” he added, showing a snap of the little bundle taken on his smartphone.

The Air Canada plane, heading from Calgary to Narita, landed 30 minutes ahead of schedule after being bumped up the queue by air traffic controllers.

The new mum was seen emerging from the plane in a wheelchair, while her partner carried his daughter in his arms.

Mother and baby were taken to hospital, where they remained overnight.

Both are said to be doing well, the Air Canada spokesman said.

The flight crew smiled and waved at press as they got off the plane.

“Everyone was clapping their hands,” a woman passenger told local television.

“She’s such a cute baby with big eyes.

A male passenger added: “This is a happy thing.”

Air Canada allows women with a normal pregnancy and no previous history of premature labour to travel up to and including their 36th week.

It was not known how far into her pregnancy the woman was when she boarded.

In March, a Qatar Airways plane was forced to make an emergency landing in Canada after a woman unexpectedly went into labour, delivering a baby boy hours after take-off.

In January, a Jordanian woman gave birth to a baby girl mid-flight over the Atlantic while travelling to New York from Amman.