Government officials have compared immigrant fraudsters to drug importers, saying they use a "shotgun tactic" to deliberately flood the New Zealand system.
Documents obtained by Newshub show a senior Immigration official describing an "endemic use of fraud" in Indian student visa applications.
Justin Alves, a risk manager based in Mumbai, said fraudsters were using "a strategy akin to the 'shotgun' approach I saw illicit drug importers use when I worked alongside Customs".
Mr Alves said this tactic was aimed at "saturating the channel with small, individual attacks in order to overwhelm the Government resources available to it".
Around 27,000 international students have come to New Zealand in the past year - 8756 of them were Indian.
Immigration Minister Michael Woodhouse has conceded that "hundreds" of students could be here illegally but says after a crackdown last year, the Government now has the matter under control.
"Thousands of these applications are being declined because they do not satisfy Immigration that they are bone fide."