A police spokeswoman said the crash happened about 2.15pm yesterday, on State Highway1 near the intersection with Mile Flat Rd.
Emergency services were called to the collision, and despite their ‘‘best efforts’’ one person died at the scene.
A second person was flown to Dunedin Hospital in a critical condition, and two other people received minor injuries.
SH1 was closed between Hampden and Oamaru for a time while emergency services worked and a scene examination was conducted by the serious crash unit.
Police are still investigating the circumstances surrounding the crash.
A reporter at the scene said it appeared a four-door sedan had taken the brunt of the damage particularly its front end.
A white ute on the other side of the road also received damage, including to its roof.
There was a large emergency services presence, including two helicopters, and multiple ambulances, fire appliances and police cars.
Because no detours were available, a queue of traffic comprising hundreds of vehicles stretched for kilometres in either direction for several hours.
One lane was reopened just before 8pm and the road was fully opened just after 9pm.
The fatal crash is one of a ‘‘concerning number’’ that police have attended on New Zealand roads over the past two weeks.
Acting director of road policing Inspector Peter McKennie said since April 20, 18 people had been killed in 14 separate crashes.
He said police were ‘‘disappointed at the concerning number of deaths on our roads’’, because police highlighted the importance of safe driving behaviours every day.
As of yesterday morning, 12 more lives had been lost on New Zealand roads so far this year compared with the same time last year, he said.
‘‘Our thoughts are first and foremost with the families who have lost loved ones so tragically in recent days.
‘‘Any death on the road is one too many.’’
However, he was ‘‘extremely frustrated’’ many of the deaths could have been avoided with safer driving behaviours.
‘‘Everyone should be extremely concerned about the rate of people being killed on New Zealand roads.’’
Nine of the fatal crashes were in 100kmh speed zones and involved a vehicle crossing the centre line and colliding with a vehicle travelling in the opposite direction.
That resulted in 11 people being killed.
Six people killed on the roads over the past two weeks were not wearing seatbelts, including one on a road with a 50kmh speed limit.
Insp McKennie said police remained committed to keeping everyone safe on the roads, but they could not do it alone.
‘‘We need everyone’s help to keep our roads safe,’’ he said.
‘‘Where we see any unsafe behaviours, you can expect to be stopped.
‘‘Simple behaviours like buckling up before you travel; not getting behind the wheel if you’re impaired by alcohol, drugs or fatigue; staying fully focused on the road without any distractions; and slowing down are crucial in avoiding crashes and deaths.
‘‘There will be no tolerance from police for those who choose to disregard road safety rules and put the lives of others at risk.’’
