Authorities are investigating after an unidentified pink substance was discovered in the upper reaches of Whangamata Harbour.
Thames-Coromandel District Council Whangamata area manager Garry Towler said the discolouration was discovered by residents this morning. It was believed to be non-toxic, water-based paint.
Contractors had since pumped the discoloured water to the wastewater system for further treatment.
No animal or birdlife had been affected and the incident occurred in an area with limited public access and at low tide, Mr Towler said.