A police spokesperson confirmed one person was killed and four people were injured, two moderately and two seriously
One of the seriously injured occupants was airlifted to Dunedin Hospital and the other three were transported to Timaru Hospital.
SH1 was expected to be closed for several hours while the Serious Crash Unit investigated.
Diversions remained in place at the intersections of Barnetts Rd and Horsnells Rd.
One dead in Northland
In a separate crash in Northland, a female died after a collision involving three cars just north of Towai.
Two other people were treated for moderate injuries.
Sergeant Daniel Cleaver said the crash was near a sharp bend just north of the Towai Tavern.
A diversion was put in place but it became blocked when a truck got stuck on the diverted roads, which were only suitable for light vehicles.
As a result traffic was diverted through Towai Rd, Callaghan Rd and Maromaku Rd.
Police advised motorists travelling through the area would need to exercise patience and factor in longer travel times through the diversions.
The Serious Crash Unit was attending the incident.
A person at the Towai Tavern said he could not quite see the accident as it was just around the corner.
He heard the fire siren go off and then traffic started backing up passed the tavern. The man had also seen a number of police cars.
A few motorists had stopped at the pub to wait for the road to be cleared.
Associate Minister for Transport Shane Jones said he was horrified to hear of the second fatal car crash on Northland roads in three days. Three people died in a horrific three-vehicle smash earlier this week.
"It's an awful tragedy and my aroha goes out to all the whanau."
He said whatever the cause of the accidents, questions about the condition of Northland roads would likely arise.
"The robustness of our roads and the need for safety is paramount.
"We need to improve the level of investment and the access to funding to enable the North to improve the most egregious conditions of our roads," Jones said.
The deaths have brought the road toll to 320 for the year so far, up 48 on the same time last year.
Queenstown school bus crash
Meanwhile, one child was injured after a collision between a car and school bus in Queenstown. Another patient suffered serious injuries.
A police spokesperson said they were called to the crash on Frankton Rd between Sugar Lane and Yewlett Cres at 3.49pm.
A St John spokesperson said two patients had been transported to Lakes District Hospital.
One patient was a 8-year-old girl with minor injuries, and another patient sustained serious injuries.
