Thousands of litres of untreated wastewater, including sewage, has been released on Wellington's south coast.
An equipment failure at Moa Point Wastewater Treatment Plant last night led to around 5,000m3 of wastewater being discharged.
It happened at the short outfall pipe near the dog pound.
Health warning signs have been put up in Tarakena Bay and Heu Te Taka Peninsula.
Wellington Water said that the beach at Lyall Bay is not affected.
Water quality testing of coastal waters is currently underway at the discharge site, and will continue for three days.
Regional Public Health has been informed.