As the driver of a vehicle, by law you must make sure that:

• Any child under five years is properly restrained by an approved child restraints. They must not travel in the car if you can't put them in an approved child restraints.
  
  
• Children aged five to seven years must use a child restraint if there's one available. Otherwise they must use a safety belt if one is available. If there are no child restraints or safety belts available [see exceptions to the law], they must travel in the back seat.
  
  
• Children aged 8 to 14 years must use a safety belt if one is available. Otherwise, they must travel in the back seat. Note: A child under 15 years of age may sit beside the driver only if the child is restrained by a child restraint or safety belt (whichever is appropriate for their age).
  

Exceptions to the law

A child doesn't have to be in an approved child restraint if they're travelling in a:

• Vintage vehicle (first registered before 1955) that isn't fitted with safety belts
  
  
• Goods services vehicle (eg, a truck, van or utility) with an unladen weight over 2,000 kg that isn't fitted with safety belts
  
  
• Passenger service vehicle (eg, taxi, shuttle, bus) that isn't fitted with safety belts
  

However, where a safety belt is available in any of these vehicles, the child must be restrained, and where an approved child restraint is available, it must be used (where appropriate for the child's age and weight).

Taxi companies will probably provide child restraints if you give them reasonable notice.

Note that the driver of a passenger service vehicle, such as a bus or taxi, is not legally responsible for ensuring seat belts are used (if fitted). It's up to the person in charge of the child to make sure they are used.

Child restraints must also...

In accordance with the law, child restraints must also be fitted according to the manufacturer’s instructions.

Example: If the manufacturer of your child restraint states that it requires you to install your seat with its top tether strap; "This restraint must be attached to a child restraint anchorage point in the car", "Do not use child restraint without upper tether strap attached to anchorage point" (or similar instructions). This is not optional. If you fail to use the upper tether strap, the driver of the vehicle can earn a $150 fine per restraint that is not installed in accordance with the manufacturer's instructions. See Land Transport Rule; Vehicle Equipment 2004; Rule 32017; Part 1; Section 2; 2.9 Child restraints.

Reference:

Land Transport New Zealand; Factsheet 7; Child restraints

Land Transport New Zealand; Factsheet 7; Exceptions to the law

Land Transport Rule; Vehicle Equipment 2004; Rule 32017; Part 1; Section 2; 2.9 Child restraints