"It's really unfortunate that she's got three children, part of our most vulnerable in our community, and for want of a restraint, hasn't done that."
She said it was worrying that safe decisions were not being made for children, who couldn't make those decisions themselves.
"Three young children could have come to something worse and that would be just a tragedy and they're tragedies that are so easily prevented," Mrs Grace said. "This is not about the enforcement. This is about the safety of these children in the vehicle."
The woman was breath tested and fined $150 and the children were restrained before she was allowed to continue home. It's not clear if there were car seats in the car.
Last month Alexandria "Lexie" Grace Navacilla died in Starship Children's Hospital after suffering critical injuries in a car accident on State Highway 4 near Aria in the King Country on May 19. The 12-week-old was one of six people in a five-seater Honda hatchback and was sitting unrestrained in her mother's lap in the backseat when the car slid across the road into a bank. Police found her car seat, which could have saved her life, in the car boot.
Her parents, originally from the Philippines, were travelling from their home in Taumarunui to Auckland.
That same week police reported a woman breastfeeding a baby while in the front seat of a moving car in Hamilton.
That incident came days after police stopped a woman driving in the city with two young children in the back seat who should have been in car seats but were instead strapped in with seatbelts.
The mother, who was breaching the conditions of her learner driver's licence when stopped, told the officer she was taking the 4- and 5-year-olds to see a doctor and that she did have car seats but her sister was using them.