Children must be in an approved child restraint until their seventh birthday after the law came in to effect on Friday.
This means, children are required to use an approved car seat until they turn seven, and seven-year-olds are to use a booster or car sear if one is available.
The rule change was agreed by Cabinet in 2012 and signed in June this year, providing parents and caregivers four months to ensure they have appropriate child restraints, such as booster or car seats.
The new law extends the mandatory age by two years. Previously, children between five and seven years old were required to use a restraint only if the vehicle had a seat or cushion.