Canterbury District Health Board is reminding people to boil water and maintain hygiene in order to prevent outbreaks of illness.
On Friday, the Cowles Stadium welfare centre was closed and evacuees taken by bus to Rangiora because of fears the centre lacked the resources to handle a disease outbreak.
Canterbury District Health Board chief executive David Meates says people need to be vigilant about boiling any water used and maintaining hygiene to prevent gastroenteritis outbreaks.
Health authorities are starting to dispense alcoholic gel at water collection points.
Mr Meates said 70% of GP practices are operating. Australian doctors and nurses are working at a field hospital set up at Cowles Stadium, treating conditions normally requiring a GP visit.
He said Christchurch Hospital's emergency department had been relatively quiet from Friday, and about 120 patients had been transferred elsewhere.
Mr Meates said it has transferred 180 aged care patients from Christchurch to facilities elsewhere, including in the North Island. He said almost all the capacity in the South Island had been used.