In a statement P&O Cruises confirmed there are currently six passengers with symptoms of norovirus:
"Oriana is currently on a 10-night Baltic cruise which departed from Southampton on December 4. There are 1,843 passengers on board, the number of passengers with active symptoms today is six (6) (0.3%). Enhanced sanitation protocols have already been implemented.
"These comprehensive disinfection protocols have been developed by P&O Cruises in conjunction with UK and US public health authorities. The safety and comfort of passengers and crew is always our number one priority.
"As is currently standard procedure across our fleet, all the ships passengers were provided with a precautionary health notice advising of widespread Norovirus activity and the health measures to avoid contraction and spread, both on board and whilst ashore."
As cases of the norovirus soar across the UK, fresh guidance is issued by clinicians on how to treat the symptoms.
The number of confirmed cases of the winter vomiting bug, norovirus, is 72% higher than at this time last year, health experts have said.