Shortly before lunchtime yesterday, a motorist saw tyre tracks in the ice on Clutha Valley Rd, and stopped to find a car upside down on a bank.
Constable Craig Gordon, of Balclutha, said the passer-by called emergency services, and helped the female driver and her two young children out of the car through a rear window.
They were treated for minor injuries.
Most of the crashes reported to police have happened on South Otago sections of State Highway 1 and 8. Ten incidents have been attributed to ice and heavy frosts.
Five crashes on State Highway 1 between Monday evening and yesterday were reported to police.
Yesterday, about 7am, a truck jacknifed after hitting ice less than 10km south of Balclutha.
The vehicle was not damaged, but both lanes of traffic were blocked for more than an hour before the truck was able to carry on its trip.
Emergency services also attended five single-vehicle crashes on State Highway 8 between Milton and Raes Junction.
Sergeant Craig Dinnissen, of Balclutha, emphasised the importance of driving to the conditions.
"Drivers need to be extra-vigilant: there is ice where you expect it to be, and there is ice where you don't expect it to be. You can't rely on all icy areas to be gritted, and even then you need to take care."
Ice-related crashes were also reported on Tokoiti Rd on Monday, and on Old Coach Rd on Tuesday and yesterday morning.
Emergency services were also called to two crashes on State Highway 1, north of Waihola, on Tuesday morning.
In Central Otago, icy roads in the Lindis Pass saw four people injured after their car ended up upside down in a creek about 1.30pm on Tuesday.
Constable Terry Saunders, of Cromwell, said he believed three of the occupants were taken to Dunstan Hospital at Clyde for treatment, and the fourth was taken to Dunedin Hospital.
One of the occupants was from Auckland, and the other three were Taiwanese tourists.
Const Saunders said drivers should be aware of ice lingering on the roads, "particularly with the hoar frost hanging around", especially in shaded areas.
Police have attributed the number of crashes to at least five days of frosts layering on top of each other.
