A bacteria which is dangerous for vulnerable patients has been found in the water supply in Christchurch Hospital's Intensive Care Unit.
The bacteria species stenotrophomonas has caused infections in two patients in the unit at the same time.
Samples of the tap water in the two ICU units also found another bacteria, pseudomonas.
Canterbury District Health Board said these types of bacteria were widespread in the environment and commonly water borne.
It said they were usually harmless, but could cause pneumonia and other infections in patients in an ICU setting.
The hospital said it no longer used tap water for bathing patients, and since this change was made there have been no more infections from these bacteria.