A wastewater main under State Highway 1 burst for the second time in a week last night due to another day of bad weather in the Wellington region.
The break in the pipe which lies between the Aotea turnoff and Paremata caused wastewater to overflow into the nearby harbour.
Wellington Water is continuing to fix the pipe today and expects more overflow of sewage.
To reduce the risk of overflow they are asking residents in Whitby, Paremata, Plimmerton, Pukerua Bay, and in the northern parts of Papakowhai, to minimise water use as much as possible.
Waka Kotahi are advising travellers to expect major delays due to the work on the pipe which has caused one lane on State Highway 1 to be closed.
The wastewater main first broke on Saturday morning after a one-in-10-year rainfall event in the capital.
The piece of infrastructure caused sewage to overflow on to Station Rd, Paremata Cres and some areas near the entrance of Paremata Primary School grounds.
The pipe was temporarily repaired on Monday afternoon however, Wellington Water's investigations showed the pipe was in a fragile condition.
On Tuesday more sewage leaked into Porirua Harbour after a plan to alleviate pressure on the previously patched-up pipe.
Wellington Water wastewater chief advisor Steve Hutchison told the Herald on Tuesday it decided to reinstate another unused pipeline across Porirua Harbour to alleviate pressure.
Hutchison said the pipeline was found to have a fault and some wastewater spilled in the northwest area of Onepoto, opposite Papakowhai, affecting the walkway and immediate area.
"The pipeline was taken offline when the overflow was discovered and the walkway has been temporarily closed."
Wellington Water is advising the public to avoid contact with coastal water in the area.