One person is dead and seven others have been injured in two separate South Island crashes this afternoon.

A pedestrian hit by a vehicle on State Highway 1 at Woodend in North Canterbury has died. The incident happened at 1.40pm, closing SH1.

Diversions remain in place and motorists are asked to avoid the area and expect delays.

Another crash in Richmond, north Otago, has injured seven people, with four patients requiring airlift to Dunedin Hospital.

The crash happened at 12.05pm.

Police said one person is critically injured and another has moderate injuries.

“Five other people have sustained minor to moderate injuries and have been transported to hospital.

“The road remains closed at this stage.”

A St John Ambulance spokesperson confirmed four ambulances and a manager responded to an incident at Hilderthorpe-Pukeuri Rd and Richmond Rd shortly after lunchtime.

The crash site is 11km north of Oamaru, in north Otago.

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Four patients required an airlift to Dunedin hospital as emergency services responded. Photo / Thinkstock

Four people were taken to Dunedin Hospital by helicopter, while ambulances took another two moderately-injured people for treatment to Timaru Hospital.

A seventh person was taken to Oamaru Hospital, also in moderate condition.