The death of a third person following a crash in the central North Island means six people died in Waitangi Day smashes yesterday.

Police said the person was involved in a crash on State Highway 4 about midday in Raetihi.

Two people died at the scene, and a third later died in hospital several hours later, police confirmed today.

A fourth person suffered moderate injuries.

Also on SH4 yesterday, one person died in a crash at Manunui, east of Taumarunui.

A motorcyclist died on State Highway 50 in the Central Hawke's Bay about 2.15pm, while about two hours later, another person died following a two-vehicle crash in Carterton.