Two people have died following an overnight crash involving two cars and a motorbike in the Christchurch suburb of Heathcote Valley.

Police said they received a report about the crash on Tunnel Road just before midnight on Saturday.

Two other people were critically injured while a third sustained serious injuries, police said.

The stretch of State Highway 74 known as Tunnel Road was reopened to traffic at about 7am on Sunday.

Police said the circumstances of the crash are being investigated.

Meanwhile, one person died after a crash in Coromandel.

Police were called at 8.45pm on Saturday after a car travelling on Te Puru Creek Road crashed into the water.

A second person suffered serious injuries in the accident, police said.

The three latest deaths bring the holiday road toll over the Christmas-New Year period to 15.

The official 2023 Christmas New Year holiday period began at 4pm on 22 December and ends at 6am on 3 January 2024.

Last year, 21 people died on the roads over the Christmas-New Year holiday period.