The highly contagious, virulent tummy bug has been afflicting the city for almost a month.
A Canterbury District Health Board spokeswoman said two wards at Christchurch Hospital were still being closely monitored for infections, while five affected were beingcleaned for re-use.
Two wards at Princess Margaret Hospital remain closed to new admissions.
The CDHB said things were improving slightly but the bug, which can pass from person to person without bodily contact, was still extremely prevalent in the community.
It urged people to wash their hands thoroughly after the toilet and to stay away from work if they had stomach bug symptoms.
