Sewage has leaked into Porirua Harbour after a plan to alleviate pressure on a recently patched-up wastewater pipe went awry.
The pipe between the Aotea turnoff and Paremata burst on Saturday morning after a one-in-10-year rainfall event in the Wellington region.
The piece of infrastructure caused sewage to overflow onto Station Rd, Paremata Cres and some areas near the entrance of Paremata Primary School grounds.
It was repaired yesterday afternoon, but remains in a fragile condition.
Wellington Water wastewater chief advisor Steve Hutchison said they decided to reinstate another unused pipeline across Porirua Harbour to alleviate pressure on the recently repaired pipe.
"Unfortunately, the pipeline was found to have a fault this afternoon and some wastewater spilled in the northwest area of Onepoto, opposite Papakowhai, affecting the walkway and immediate area," Hutchison said.
"The pipeline was taken offline when the overflow was discovered and the walkway has been temporarily closed."
Daily water testing will continue and people are being encouraged to avoid swimming in the area until further notice.
Greater Wellington Regional Council advised it has closed the coastal track at the Onepoto end of Whitireia Park due to the sewage leak.