Private tertiary institutions say they are losing hundreds of enrolments from the Philippines and India because Immigration New Zealand is taking a tougher line on students' savings.
As well as tuition fees, international students must have enough money to cover their living costs - $1250 for every month of study, or $15,000 for a full year.
Independent Education New Zealand chairperson Christine Clark said Immigration New Zealand was looking much more closely at where prospective students had got that money from.
"If the student says they've borrowed from aunty, they then ask how many hours aunty works, and how much she gets paid per hour and how long she's worked in that job etc., and they'll just say 'nup doesn't add up, declined'."
Ms Clark said the new approach was "absolutely crucifying" private providers trying to enrol students from the Philippines.
The Philippines is a rapidly growing source of students, with study visa applications roughly doubling in the last two years to about 4000.
Historically, Immigration New Zealand has turned down 12 to 15 percent of Filipino study visa applications but in November last year it turned down 42 percent and in March this year it refused 31 percent.
National Trade Academy managing director Craig Musson said the leap in declined applications was having a major impact on institutions like his.
"Whereas 18 months ago we had 20 or 30 Filipino students coming through, we've dropped down to four or five. We're really struggling and our visa decline rates are going up - not because we're not getting enough students, but because they're struggling to prove their source of funds.
Mr Musson said Immigration was asking for financial records that many students simply didn't have.
"Some countries, which especially are cash societies, they just don't have a record of these things. The amount of money that Immigration offshore are asking for is making it very difficult. It's like the students are just not being believed. Everybody's being treated as though they're money laundering."
But Immigration New Zealand area manager Michael Carley said its Manila office's scrutiny of applicants' finances was consistent with its other offices.
"This is to ensure that students have sufficient funds to support themselves while in New Zealand. As is the case in many offshore markets, INZ (Immigration New Zealand) may also assess the source of the funds being presented, to ensure that they are genuine. "
Mr Carley said Immigration was making more robust checks of applicants' finances in India, and applying new English-language requirements.
But he said that had not led to an increase in the proportion of failed study visa applications.
Rather, the opposite had happened, with the monthly rate of decline falling from 73 percent in November last year to 48 percent in March this year.