State Highway One has been closed following a serious crash at Mangamaunu, north of Kaikoura.
The head-on crash happened about 4pm and involved a four-wheel drive vehicle and a camper van.
The male driver of the camper van has been flown to Wellington Hospital in a serious condition. His female passenger was uninjured.
The sole occupant of the four-wheel drive has been flown to Christchurch Hospital, also in a serious condition. Both men had to be cut from their vehicles.
Sergeant Julian Lewis of Kaikoura said it was likely the state highway would be closed until about 8pm.
He said the crash occurred on a slight bend and weather at the time was good. A serious crash investigation is under way.