A broken sewer has closed several roads in Christchurch.
Civil Defence says the collapse was caused by ground subsidence following the February earthquake and raw sewage is now being pumped directly into the Heathcote River.
Ferry Road is closed between Charlesworth Street and the Ferry Road roundabout, however an alternate route is available on Dyers Road, Humphreys Road and Linwood Avenue.
Civil Defence director of infrastructure Jane Parfitt says the collapse is a setback and shows how fragile the wastewater system is.
Ms Parfitt says residents can expect similar events as the city gets back onto its feet.
It could take several weeks to put a temporary fix in place.
Residents in the area are advised to continue to use chemical toilets and portaloos.