It is a grim weekend on the roads across the country, with multiple crashes leaving four people dead on Saturday.

A person died and two others are being treated in hospital following a crash in the western Bay of Plenty on Saturday night.

The police say the crash happened on State Highway 2 in Pukehina shortly before 11pm. Detours are in place and an investigation is ongoing.

Emergency services also responded to a serious vehicle collision on Settlers Road in Reporoa in the Bay of Plenty just after 6pm.

Police say initial indications suggested there were serious injuries. Motorists were advised to avoid the area.

In another fatal crash in the North Island, one person died after a vehicle reportedly hit a tree on Masters Road, Waiuku in the Auckland region about 2pm. Another person was taken to hospital in a serious condition.

Two people died in Hororata after a single motor vehicle crashed shortly before 3pm Saturday on Rakaia Terrace Road in the Canterbury plains town, west of Christchurch.

Three other people were taken to hospital with what police are calling "a range of injuries". St John say that two ambulances, two helicopters, a rapid response vehicle and an operations manager responded.

Diversions were in place on and police encouraged motorists to avoid the area.

A pedestrian was injured in another car crash in Dunedin just before 7pm.

Police say one person was seriously injured in the accident on Main South Road and the off-ramp there would be closed for some time.

RNZ