Wellington's Hutt Hospital has confirmed an outbreak of norovirus while Dunedin Hospital battles to get on top of the virulent stomach bug.
Eleven patients at Hutt have now contracted the virus, with some staff being sent home to recover.
Hospital spokesman David Graham told the Dominion Post adjoining wards, with 54 beds between them, remained closed to new admissions and visitors were being urged to keep away.
An orthopaedic ward at Dunedin Hospital remains closed after five patients and a staff member contracted the virus on Sunday.
There have been no new cases since then but some surgery was postponed yesterday, partly due to bed shortages which coincided with the suspected norovirus outbreak.
Elective surgery is expected to be back to normal today.
Dunedin Hospital was badly hit by an outbreak of the virus in August, which, at its worst, affected more than 170 staff and patients.
Norovirus is a highly contagious virus that causes nausea, vomiting, abdominal pain and diarrhoea.