One person has died after a car left State Highway 6 in Northern Southland on Tuesday afternoon, closing the main road between Lumsden and Dipton for about five hours.

Police said emergency services were called at about 1.10pm on Tuesday 3 November to a crash on the highway just south of where Josephville-Glenure Road meets SH6. Only one vehicle was involved.

In an early statement police said one person was understood to have serious injuries. Shortly before 7pm they confirmed the person had died at the scene.

Hato Hone St John told the NZ Herald it was alerted at 1.06pm and sent an ambulance, an operations manager, a first response unit and a PRIME rural doctor or nurse to the scene.

The highway was closed at Josephville, from the Caroline Valley Road turn-off in the south to Josephville-St Patricks Road in the north, while the Serious Crash Unit examined the site. The NZ Transport Agency posted a detour for northbound traffic via Dipton-Castlerock Road and State Highway 94, the Mossburn-Lumsden Highway, with southbound drivers following the same route in reverse. The road reopened at about 6pm.

Police have not released the name of the person who died, and have given no details of their age or where they were from. The Serious Crash Unit's findings will go to the coroner in the usual way, and police have not commented on what might have caused the crash.

The stretch of SH6 between Dipton and Lumsden carries much of the traffic between Invercargill and Queenstown, as well as stock trucks and milk tankers serving Northern Southland farms. It is open, rolling country where the highway runs beside the Oreti River and crosses several side roads at speed.

It is the second fatal crash on SH6 in the lower South Island in five days. On Friday 30 October a two-vehicle crash in the Kawarau Gorge, between Cromwell and Queenstown, killed one person and closed that part of the highway into the night.

Tuesday's death comes as the region heads into the busiest stretch of the farming and holiday calendar, with the Tour of Southland cycle race using Southland roads this week and election day on Saturday expected to put more traffic on the highways.

Anyone who saw the crash, or who was travelling on SH6 near Josephville shortly before 1pm on Tuesday and has dashcam footage, can contact police on 105 and refer to the Lumsden-Dipton crash.

Update, 6 November: police have named the woman who died as Kararaina (Kara) Aroha Toimata, 30, of Balfour, and are asking to hear from anyone who saw a white Toyota Hilux travelling north on SH6 at about 1pm that day. Read the latest story.