The woman who died when her vehicle crashed on the Lumsden-Dipton stretch of SH6 on Tuesday was Kararaina (Kara) Aroha Toimata, a 30-year-old from Balfour in Northern Southland, police said on Friday.

In a statement released early on Friday afternoon, police extended their condolences to Ms Toimata's family and friends and said the inquiry into the crash was continuing.

At the same time, they asked for help from anyone who was on the highway at Josephville around lunchtime on Tuesday 3 November. Officers want to hear from people who saw a white Toyota Hilux double-cab ute with a flat deck and a large silver toolbox on the back, travelling north on SH6 at about 1pm.

Police said the ute may have been waiting at the temporary traffic lights at roadworks just south of the Josephville hill, alongside other vehicles, shortly before 1pm. They have not said how the ute relates to the crash or whether they consider its driver a witness.

The Invercargill Herald reported on Tuesday that emergency services were called at about 1.10pm to a crash just south of the Josephville-Glenure Road intersection. Only one vehicle was involved. The highway was shut between Caroline Valley Road and Josephville-St Patricks Road for about five hours while the Serious Crash Unit worked at the scene, with traffic sent around via Dipton-Castlerock Road and SH94. Police confirmed that evening that the person had died at the scene.

Balfour is a small farming settlement about 15 kilometres east of Lumsden on the Waimea Plains, and the Lumsden-Dipton stretch of SH6 is the everyday route south for people who live there.

Ms Toimata's death was one of three on southern highways in the space of a week, and on Friday evening the Southern district's road policing manager, Inspector Craig Brown, issued a plea to drivers ahead of what he called a busy season on the roads. The other two fatal crashes were in the Kawarau Gorge on Friday 30 October and on SH1 near Clinton on Friday morning.

Inspector Brown said all three were still being investigated, and listed the four behaviours police see most often in deaths and serious injuries: speed, not wearing a seatbelt, distraction and driving impaired by alcohol, drugs or fatigue. He singled out open roads with limits above 80km/h and no median or roadside barriers, where he said a single error can be fatal, and urged people to plan long trips and take breaks.

The Otago Daily Times also reported the name release and the appeal on Friday, as did the NZ Herald.

Anyone who saw the white Hilux, or who was stopped at the Josephville roadworks lights before 1pm on Tuesday and has dashcam footage, is asked to call police on 105 or make a report online at 105.police.govt.nz, quoting file number 261103/5423.