The woman was the driver of a northbound car which crossed the centre line, striking the edge of a southbound car in the oncoming lane, causing minor damage to that vehicle, Sergeant Pete Muldrew said.
The northbound car then continued in the oncoming lane and struck another southbound car, causing major damage to both vehicles.
It was understood some of the occupants of the two southbound vehicles were taken to Oamaru Hospital, while the child, who was flown to Dunedin with her grandmother, was not believed to have been injured.
The crash occurred about 1.40pm at Waiareka Creek, just south of Totara Estate, and the road was reopened just before 4pm.
No further details were available last night.