The Government has only a tepid commitment to promoting child passenger restraints, following a rule change last year, a new study says.
The law was changed in November last year, requiring children be in approved restraints in vehicles up to the age of seven, instead of five.
But according to Auckland University-led research, New Zealand has significantly higher rates of child passenger injury compared with other countries.
The study, published in the New Zealand Medical Journal, calls for children to remain in a booster car seat until they reach 148 centimetres in height, usually by the age of 12.
Co-author Elizabeth Segadin says it's up to health professionals including GPs to advise parents on the correct use of restraints based on the science, even though the law has set an age limit of seven.
The study says the law change is a step forward but further changes are needed, such as making taxis and buses have the correct booster seats for children.
The Paediatric Society of New Zealand is also calling for health professionals to actively promote the correct use of restraints.
Plunket says it has been promoting the use of booster seats for children beyond their seventh birthday, as have most child safety organisations.