The woman and children, one believed to be an infant and the other a pre-teenage child, were in a Toyota four-wheel-drive when it rolled above the Skipper's Rd turn-off, at 1pm.
The trio suffered minor injuries and were taken by St John Queenstown ambulance to Lakes District Hospital.
No other vehicles appear to have been be involved.
NZSki transport manager Etienne Raubenheimer said at the scene an ambulance had already arrived two or three minutes before he did.
Mr Raubenheimer said ambulance officers attended to the occupants, while motorists pulled over to help, and he secured the Toyota to his ute to prevent it sliding down the incline.
Constable Dave Felstead, of Queenstown, said further details were unavailable yesterday.
Inquiries were continuing and he hoped to speak to eyewitnesses today.
