A police spokeswoman said officers were called to a two-car crash at the intersection of Challis St and Glendevon Pl, just off Larnach Rd, about 7.45am.
One person received serious injuries, the spokeswoman said.
Senior Sergeant Anthony Bond, of Dunedin, said the crash happened when a 69-year-old woman allegedly failed to give way and her vehicle collided with a car coming up the hill.
The spokeswoman said officers were also called to reports that a truck had slid on ice at the corner near the bridge in Townleys Rd, Kenmure, and became stuck on a barrier, about 8.05am.
Nobody was injured. A heavier truck was involved in a similar incident shortly afterwards, she said.
Tru-Bilt Industries operations manager Paul Taylor watched the scene unfold from across Kaikorai Valley.
The first truck coming down the hill spun through 360 degrees, crashed into the barrier and caused a blockage in the lane, Mr Taylor said.
The larger truck tried going up the hill on the wrong side of the road, but lost traction with its wheels spinning on the black ice.
Just before the crash, the weather had taken a turn for the worse and it had started to rain.
Loss of traction was an ongoing issue on the road throughout the year as whenever the road got wet, trucks started losing traction, Mr Taylor said.
Three people were taken to Dunedin Hospital with injuries as a precaution but none were seriously hurt.
A police spokeswoman said the road had been icy and the council had been contacted to provide grit.
A Dunedin City Council spokeswoman said contractors were out gritting some roads and treating them with the de-icing agent CMA on Monday night.
An early-morning rain shower and freezing temperatures affected many roads throughout the city which were not normal ice hotspots.
Motorists were reminded to allow extra time, care and attention when driving in cold weather, which was expected to last the rest of the week, the police spokeswoman said.
