Two paediatric specialists at Auckland's Starship Hospital are criticising the Government's latest approach to seatbelt safety.
Its transport plan, released last week, says New Zealand has fallen behind international best practice in child seatbelt use but makes no commitment to modifying the law.
Dr Gabrielle Nuthall and Dr Liz Segedin say children aged five and over are suffering horrific injuries because they are being restrained using adult lap belts and sash belts.
They say it should be compulsory for every child up to 148cm tall to use a booster seat.
That restriction would mean most children would not be able to use an adult belt until they are aged nine to 12.
Transport Minister Steven Joyce says the Government is at least two years away from making on a decision on whether to strengthen seatbelt laws.