Oamaru and Alexandra police praised the parents involved for ensuring the children were buckled into child safety seats.
About 9am, a 39-year-old Omakau woman and her two children, aged 2 and 4, were in a car which rolled on State Highway 85, near Chatto Creek, about 14km from Alexandra, landing on its roof in a drainage ditch.
A 27-year-old Oamaru woman and two children, both aged under 3, were in a car which crashed down an embankment on a notorious stretch of Weston-Ngapara Rd at 9.40am.
Constable Ross Lory, of Oamaru, said the car left the road in icy conditions, then rolled before ending up in a ditch, about 9.40am.
Fortunately, nobody was injured.
Const Lory said "luckily" the children had been strapped into their child safety seats.
He added that ice on the road was the cause of the crash.
"The car has just come round the corner and hit the ice, left the road and obviously rolled."
"Over the years" there had been previous crashes on the same section of road, near Queen's Flat, and the issue of ice had been a recurring theme, he said.
Sergeant Dave Greaves, of Alexandra, said being buckled into properly fitted children's car seats probably saved the lives of the two Omakau pre-schoolers in the Chatto Creek crash.
"'The driver has hit black ice on the bridge and appears to have lost control of the vehicle, which rolled on to the roof and went through a fence, sliding before coming to rest in a drainage ditch."
The driver received medical treatment for a sore neck but the children were uninjured apart from "scrapes and bumps". He praised members of the public who helped after the accident, including the person who used a knife to cut the driver's seat belt so she could be removed from the car.
The accident was a "stark reminder" to be cautious when driving on Central Otago roads during winter, he said.
The highway was closed for about an hour.
Police were called to two non-injury crashes near Milton yesterday.
Senior Constable Steve Griffiths, of Milton, said shortly after 10am a 40-year-old Wanaka woman lost control of her car on State Highway 8 in the Manuka Gorge, after skidding on grit.
One lane was blocked for about 40 minutes.
At 3pm, a car driven by a 38-year-old Milton woman slid into a bank before coming to rest on the side of the road on State Highway 1, about 12km south of Milton.
Snr Const Griffiths said he believed the woman had no major injuries but was taken to Dunedin Hospital for observation as she was pregnant.
