https://www.immigration.govt.nz/opsmanual/#34295.htm
看: Dependent children of New Zealand citizens or residence class visa holders may be granted a visitor visa authorising a maximum stay of 9 months from their date of arrival
If dependent children apply to stay longer than 9 months, immigration officers may consider granting further visas allowing a total stay of up to 2 years as long as the requirements of paragraph (a) above continue to be met.