A four-month-old girl has died while travelling on a Cathay Pacific Airways flight from London to Hong Kong.

The infant is believed to have been suffering from a gastrointestinal disease when the family boarded the plane at Heathrow on Sunday.

She fell unconscious during the flight and her parents - who were planning on visiting relatives in China – alerted cabin crew immediately.

Another passenger – a nurse – started giving first aid to the baby.

The pilot made an emergency landing at Almaty Airport in Kazakhstan and paramedics rushed to the scene.

But the baby could not be saved and she was pronounced dead soon after the emergency landing.

Her mother – believed to be a 36-year-old Chinese-French national - and father - continued the journey to Hong Kong with their dead child.

Fellow passengers said they were emotionally distraught during the rest of the flight.

The baby's death was confirmed by officials but is not being treated as suspicious. A post-mortem examination is yet to take place.

A doctor told Apple Daily that parents should avoid taking sick babies onto planes as a “lack of medical support could lead to very dangerous situations on board."