It said the pipe was blocked with garden waste, and caused wastewater to back up and manholes to start popping - coming at a time when the network recently dealt with heavy rain.
The council asks residents to avoid fishing, swimming, or gathering shellfish in the river and beaches until the emergency sewer valve is closed after the blockages are removed.
Council spokesman Dave Hadfield said it was especially disappointing this has happened when water users like waka ama are training for national competitions.
Hadfield said it was frustrating that people deliberately disposed of green waste irresponsibly.
“It’s actually a deliberate act to cut, you know a size of a manhole is quite small, but to deliberately cut branches to that size so you could fit it in is a deliberate action, that’s what we’re so disappointed about.”
While an initial blockage was cleared on Monday evening, Hadfield believed there could be multiple blockages in up to 500 metres of sewer pipe in the Mangapapa area.
Contractors will put cameras into the pipes on Tuesday morning to locate them.
It could be difficult to find the people responsible as there were many manholes on private property in the area affected, Hadfield said.
- RNZ
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