French authorities on Wednesday allowed asymptomatic passengers to leave a British cruise ship, saying a gastrointestinal virus was behind an outbreak of sickness that came after an elderly man died of a heart attack.

A French hantavirus patient is critically ill as total cases from the cruise ship outbreak rise to 11, raising concerns.

Hundreds of passengers - mostly British and Irish - on a cruise ship have been quarantined in the French port of Bordeaux after a death on board.