A New Zealand tannery is being prosecuted by the Auckland Regional Council (ARC) for polluting local air and water.

Campbell Sturrock from ARC said that legal action is being taken against Affco New Zealand Limited for unauthorised discharges of contaminants into the Homai stream, a tributary of the Puhinui Estuary in Manukau, and also for discharging into the air.

"On February 16, the ARC Pollution response team noticed the Homai stream in Wiri was flowing a dark brown colour with white, greasy scum on its surface. In addition there was a strong odour in the area of the stream, and many eels and invertebrates had died," said Mr Sturrock. "Samples of the stream water and foam matched samples taken from the Affco site."

ARC environment management chair, Dianne Glenn, said Affco is currently operating without a resource consent for its discharges to land and as a result of this ARC is charging Affco with continuing to discharge contaminants from the site without authorisation.

A date has yet to be set for the prosecution to be heard in the Environment Court.