Porirua's wastewater treatment plant has overflowed as a result of the storm that's hit the Wellington region.
The Porirua City Council has warned people to stay out of the flood waters caused by the storm, and also the sea until further notice. The council confirmed the spill on a Facebook post, saying it was expected.
It comes as wild weather has caused flooding havoc around Wellington, with highways and roads closed, and power outages too.
The Porirua council said some homes in Pukerua Bay and Plimmerton are without power.
Flooding has closed SH58 Pauatahanui to Haywards Interchange and SH 58 Whitby, between the intersections with Postgate Drive and Spinnaker Drive.
MetService has issued a severe thunderstorm watch for most today and into the evening.