Immigration Minister Nathan Guy says any risks arising from a deal with China Southern Airlines to fast-track visas for some passengers can be managed.
From next week members of the airline's frequent flier club won't have to show they have sufficient funds to support themselves or provide details of their employment history.
A leaked email from a senior Immigration Department official says that under the deal, criminals could enter the country undetected.
It warns that frequent flier membership is no guarantee a passenger won't be a security risk.
New Zealand First says the deal compromises the integrity of the immigration system but Mr Guy says high-net-worth passengers will still need to obtain visas, and pass health and good character checks.