Located near Brisbane, Dr Kari Jarvinen from the Metro South Public Health Unit told the Australian Broadcasting Corporation that, initial drinking water testing at Moreton Island's Tangalooma Island Resort revealed the presence of the bacterial infection E.coli.
"Anyone on the resort or anyone who has recently visited the resort should be alert for symptoms of gastro-enteritis and seek medical advice if they have concerns," he said.
"Initial reports to Queensland Health involved 50 cases, however the exact number of people potentially affected is unknown."
"All guests and staff have been advised to boil their drinking water or use commercially supplied bottled water until the issue is resolved."
With management now undergoing "advanced cleaning and sanitisation regimes," a spokeswoman for the luxury getaway said, "we are currently working with both Queensland Health and Queensland Ambulance Service to ascertain the exact numbers of guests and staff who have been affected and have also attempted to contact all guests who have departed the resort over this time."
"Some of our guests and staff have reported illness consistent with nausea, vomiting, diarrhoea, stomach cramps and a general feeling of being unwell."
Later Tuesday, further testing is expected to be carried out as authorities attempt to discover the exact source of the contamination.
The spokesperson for the Tangalooma Island Resort added, "There have been a number of cases we are aware of where guests have arrived to the resort recently with what appears to be viral infections consistent with Gastroenteritis, that was contracted prior to arrival."