A dive squad will tomorrow search the Waikato River for a person who went missing there when they got into trouble late last night.
Police were called to a part of the river near Hamilton Gardens about 9.45pm last night.
"A second person went into the river in an attempt to save them, however was sadly unsuccessful," police said.
Officers today searched the area by boat, to no avail.
The Police National Dive Squad will tonight travel to Hamilton to assist in the search tomorrow.
St John was called to the scene and assessed the second person, before they were taken to hospital for treatment. Their condition is not yet known.
"A police boat will search the river and its banks this morning for the outstanding person."