The Government has raised the age until which children have to use approved child restraints in motor vehicles.
At present, children have to be in approved car seats or booster seats until they are five years old, but this will increase to seven on 1 November this year.
Children aged seven or eight will also have to be in a car seat if there is one available in the vehicle.
Associate Transport Minister Michael Woodhouse says the changes bring New Zealand into line with countries such as Australia and Japan and is aimed at improving safety and reducing injuries.
Mr Woodhouse says parents and caregivers have more than four months to buy appropriate child restraints for children who have stopped using them or grown out of their old ones.