St John was also called to an accident in Dairy Flat, Auckland, where a car ended up in a ditch. A person suffered moderate injuries and was taken to North Shore Hospital for treatment.
Earlier, two people were taken to Waikato Hospital in a moderate and serious condition following a crash in Piarere. Another person suffered serious injuries in a crash in Raumanga just before 6.30pm.
Read more:
• Two dead in Waimate crash, bringing Christmas road toll to seven
• Two seriously hurt as second major crash in Canterbury blocks highway
• Car crashes through fence in Cockle Bay, Auckland
About 5.15pm, a four car pile-up in Lindis Pass resulted in five people being injured - one of them seriously, the others with minor injuries. A helicopter helped to airlift them out to Dunedin and Oamaru.
While in Auckland, just after 6pm, another multiple car-crash involving seven vehicles led to six people being hospitalised. Three people suffered serious injuries, two moderate and one with minor injuries. All were taken to Middlemore Hospital.
The first of the South Canterbury crashes, in the Glenavy locality, led to the diversion of vehicles around the site.
The later crash happened at 11.40am at the intersection of State Highway 1 and Orari Station Rd, at Orari, 20km north of Timaru.
The police said at least two people were seriously injured. St John Ambulance said four others were taken to hospital suffering moderately-serious injuries.
The casualties were taken to Christchurch and Timaru hospitals. Those with the worst injuries were flown by helicopter.
The road was blocked for more than an hour and long queues formed. The state highway was closed between Rangitata and Timaru.
In Southeast Auckland's Cockle Bay, resident Heath Moore was woken by a bang as a silver Toyota Corolla sedan crashed through his timber-paling fence.
"Around 8.30 this morning I was inside sleeping. We heard this massive bang and so we raced outside and a guy [had] come around the corner in his car and ploughed straight through the fence."
The road was wet and the driver, a man, had lost control on a fairly tight corner, said Moore.
The driver admitted to Moore that he had been drinking, but said it was "just a few."
Moore said it was lucky no children were playing in the yard at the time.
"We have three to four kids staying with us, it could have been them. Somebody could have died, somebody could have been injured."
For counting the road toll, the holiday period this year started at 4pm Friday and ends at 6am on January 4. The fatal crashes prior to today's South Canterbury fatal collision were:
• Jie Hu, a 23-year-old from Rotorua, died in a three car pile-up on SH5 near Hamurana in Rotorua on Sunday.
• A person was killed Sunday on Pourerere Rd in central Hawke's Bay after a car rolled down a bank.
• Boney Biju died on his way home from his 21st birthday party when his car left the road and struck a tree near Hanmer Springs on Christmas Eve.
• Fijian national Lalita Devi was a passenger in a car that crashed on SH14 at Maungatapere on Saturday.
• On Friday. taxi driver Abdul Raheem Fahad Syed, 29, died in central Auckland when his car was hit by another.