The newest ship to join Tui's Marella Cruises has been hit by an outbreak of the norovirus stomach bug only a month after launching.

Marella Explorer 2 was welcomed into the fleet in April in a gala ceremony in Malaga headed by X-Factor winners Rak-Su. It had just undergone a massive refit that added features including a champagne bar and pizza restaurant.

The adults-only ship is currently crusing the Mediterranean from Naples.

A spokesperson for Marella’s parent company Tui said "a small number" of customers on board last week had reported feeling unwell.

A statement read: “We are working closely with our team to monitor the situation and have implemented additional health and safety procedures on top of already stringent protocols to prevent any further customers falling ill.

“We’d like to reassure customers that this week’s itinerary continues to operate as planned and would like to remind customers that we regularly audit all of the cruise ships we feature in respect of health and safety, including hygiene.”

It is understood that passengers are currently being served in the buffet, rather than helping themselves, which is standard procedure during outbreaks of norovirus and prevents infected travellers from spreading germs.

Five incidents of the so-called winter vomiting bug have been reported on cruise ships this year (despite the name it can strike any time of year), according to the US-based Centers for Disease Control and Prevention (CDC).

In February, 110 passengers and crew were reported ill on Princess Cruises’ Island Princess, while nearly 600 were sick on Royal Caribbean International’s Oasis of the Seas in an outbreak in January.