The Ministry of Health has recently updated their website in respect of electronic e-cigarettes.
This is in particular regard to The Medicines Act 1981 (Medicines Act) and the Smoke-free Environments Act 1990 (SFEA) regulating the sale, advertising and use of e-cigarettes and the liquids used in e-cigarettes.
Under The Medicines Act and the SFEA, people can import nicotine-containing e-cigarette products for their own use only. This is generally considered to be up to a 3 months' supply. These imported products cannot be supplied, sold or be given away to anyone else.
Importers should familiarise themselves with the import controls on these items and the capsules/liquid used in them.
You can find more information here: http://www.health.govt.nz/our-work/preventative-health-wellness/tobacco-control/advice-use-e-cigarettes