Constable Phil Hamlin said the accident happened just before 7am.
"It appears the driver's been reversing the truck into an area and with the icy, snowy morning, it has skidded and one of the wheels slipped off the side of an embankment and [the truck] overturned. It was two-thirds loaded with grit so quite weighty and rolled down into the gully about 20m," he said.
The 56-year-old driver was treated by a ski patrol for minor injuries and transferred by ambulance to Lakes District Hospital.
NZSki chief executive James Coddington said the driver was a "little shook" after the accident.
"We had a maintenance work truck spreading grit and as it backed into car park two, it went on to a false edge made of snow. The false edge gave way and the back tyres went down and it rolled once before coming to rest. It didn't go too far down and only did one roll," he said.
The driver suffered lacerations to his head and hands and was discharged from the hospital at 11am.
"He is obviously fairly traumatised. He has worked with us for at least five years. He's been spreading grit for five years. It was no fault of the driver. It was unfortunate that the bank gave way," Mr Coddington said.
