Emergency services were called to the crash in Highcliff Rd, Dunedin, about 10.30am yesterday.
The driver was taken to Dunedin Hospital with serious injuries and the child with moderate injuries, St John South Island communications adviser Ian Henderson said. Both were transported by ambulance.
Otago coastal road policing manager Senior Sergeant Phil McDouall said the cause of the crash was under investigation, but alcohol and drugs were not suspected to be factors.
The child was correctly restrained in a car seat in the back seat of the car, he said.
Senior Sergeant Stephen Larking said the car was extensively damaged.