About 50 MediaWorks staff and clients are returning from Fiji after falling ill with suspected gastroenteritis.
The group of were part of a 130-strong travelling contingent who had been staying at an island resort.
While an official diagnosis of the cause of the illness is yet to be confirmed, the emergency department North Shore has been notified.
MediaWorks said the majority of those felled by the mystery illness were now on the mend.
