Police and child welfare authorities are hunting a woman who was spotted breastfeeding and driving at the same time, with three other children in the car.
In a move called "highly dangerous", the woman attracted attention with her erratic driving at Kamo, near Whangarei.
Police, who did not catch her in the act, were called by a concerned member of the public who took down her car's registration, local radio reported.
The Child, Youth and Family Service would also investigate, after reports the woman had three other children in the car as well as the baby.
Health policy and breastfeeding expert Dr Judith Galtry said breastfeeding while driving was "very strange".