More cases of the stomach bug Norovirus have been reported at Middlemore Hospital in Auckland.
A further three patients and three staff members have fallen ill, taking the total number of cases to 18.
The patients were being treated in adjacent wards, but now those admitted to the hospital and suspected of carrying the bug will all be treated in one ward in an attempt to isolate the infection.
A spokesperson for Middlemore Hospital, Lauren Young, says clinical staff believe the virus is coming in from the community with patients.
She says staff are taking every precaution to stop it spreading within the hospital and urging all visitors to take extra care and thoroughly wash their hands.
A total of seven patients and 11 staff members have fallen ill since Thursday with suspected cases of the gastroenteritis bug.
It's not known whether the staff who contracted the bug were working on the wards in which the first group of patients fell ill.