One person is dead after a group of four were swept down the Waikato River.

The incident occurred when the vessel they were in overturned.

Police were called to Port Waikato near Ngahinapouri Island about 3pm.

The incident happened near Hoods Landing, about 10km south of Waiuku.

Police said three people were taken safely to shore by Coastguard rescuers and were then taken to Middlemore Hospital for treatment.

The fourth person was confirmed dead at the scene.

Police inquiries are continuing. The Fire Service and St John Ambulance also attended the incident.

No further information would be released until next of kin have been advised, police said.