Fonterra has accidently spilled 170,000 litres of milk into the sea.
The spillage occurred at its Whareroa plant in Taranaki with the milk going straight into the Tasman Sea.
The leak left globules of fat dispersed along the foreshore of Ohawe and Waihi beaches, near Hāwera.
At this stage, the leak has been blamed on a faulty valve which forced milk down the wastewater drain by mistake.
A similar event occurred in 2008 where Fonterra was fined $750 for a 110,000-litre leak.
The Whareroa factory employs about 1000 people and processes up to 12 million litres of milk per day. It collects milk from around 1500 farms Taranaki farms.