Not cheap taking the kids

When do children stop being children?

At the Auckland Zoo, it's when they turn 15.

On Air New Zealand flights, it starts at age 12, while on an Interislander ferry childhood stretches until 18.

Families planning school holiday outings for the kids may be surprised to discover a huge variation in the age at which children are eligible for discounts.

The zoo recently considered lowering the maximum age for child tickets to 14. It said the move was to give consistency to policies on unaccompanied children, as 15-year-olds were considered old enough to enter the zoo without an adult, but were charged a child price.

The board has put the change on hold while looking further into how children are charged elsewhere.

Many attractions, such as Auckland's Kelly Tarltons and the Sky Tower, allow children aged up to 14 to buy child tickets.

On an Intercity bus, anyone 13 and over will pay full fare, while on most flights, age 12 and up is considered an adult.

Infants are generally free, but the age at which fares start to apply ranges from two to five.

And if you're taking the kids to see the Wiggles at Auckland's Vector Arena, there's no child prices at all, just a minimum charge of $27.50 a seat, regardless of age.

Child pricing structures vary massively on transport, depending on whether you are catching a bus, boat or plane.

Interislander spokesman Nigel Parry said extending child fares to anyone 17 or younger was aimed at making the ferries affordable for families.

"We're mindful that it can be a fairly expensive exercise if you have a family," he said.

Auckland mother-of-two Leanne Johnson said the cost of children's ticket made a big difference. As her son is now 17, they can no longer buy family passes at the movies, which only cover two adults and two children.

Johnson said: "Even if you've got one who's a child and one who's a student, it's not applicable, so you've got to buy the tickets individually."

Her daughter Ella, 14, said she thought 16 was a fair cut-off age, as that's when "you can work and have your own money to spend".

Consumer NZ adviser Maggie Edwards said some transport concessions may be imposed by local authorities, but it's otherwise up to businesses to set their rates.

There is no legal definition of what constitutes a child for the purposes of pricing.

Under law, a child can be left alone without adult supervision at 14, can start full-time work and leave home without parental consent at 16, and can vote and buy alcohol at 18.