The serious crash unit is still investigating multiple fatal crashes in the Bay of Plenty and Waikato that have happened in the past couple of days.

The Bay of Plenty fatal crash happened on Sunday on State Highway 29 on the Lower Kaimai ranges.

Emergency services were called to the scene of the single vehicle accident at around 6.20am.

A police spokesperson says the serious crash unit is investigating and will determine the cause of the crash.

The serious crash unit is also still investigating a fatal truck crash that happened in the Coromandel yesterday afternoon.

The driver and sole occupant of the vehicle went off the Kopu-Hikuai Road and went down a bank about 3km from Kopu.

Police is also aware a number of people would have seen the crash or come across it shortly afterwards, and then have left the scene.

'We would appeal for anyone who saw what happened and has not yet spoken to Police to come forward,” say a police spokesperson.

They can either speak with their local police or phone Hamilton Police Station on 07 858 6200.