A fault has occurred in the ultraviolet disinfection system of the Collingwood wastewater treatment plant in Golden Bay.
This means partially treated wastewater is being discharged into an adjacent stream which in turn flows into a tributary of the Aorere River near White Bridge.
Although the discharge is partially treated and will be highly diluted, there is a potential health risk.
As a precaution people should avoid contact with the water and not take shellfish or whitebait in the immediate vicinity until further notice.
Warning signs have been erected in the area.
Our engineers are working on the problem but at this stage we’re unable to say how long it will take to fix.