Multiple cases involving the sale of fake and non-existent senior position jobs to migrant workers are being investigated by the Labour Inspectorate.
Researcher Danae Anderson said the practice was widespread and many of the students who paid for the jobs end up as victims of labour exploitation.
"There are not jobs out there for the locals, and Immigration's requirement of a management level job ... is simply impossible, especially for those who do not have local work experience and whose English is not up to scratch," Ms Anderson said.
"The real problem here is that the policy is flawed and the expected level at which these graduating international students are to enter the job market is unrealistic.
"Many have become victims of exploitation as a result, being held ransom by employers because of their visa conditions and paying thousands of dollars for non-existent and fake management position jobs."
Immigration New Zealand rejects Ms Anderson's claim that the skilled migrant policy, which requires migrants to obtain skilled or managerial jobs before they can be approved residence, is flawed.
Under the graduate job search work scheme, students who have completed their qualifications in New Zealand are given up to 12 months to find a job and apply for a further visa.
"The purpose ... is for students to gain work experience that may enable them to obtain the skilled job and thereby qualify for residence,"said agency spokesman Marc Piercey.
"It is our view that the policy is not flawed. New Zealand rightly selects only the best and most skilled people for residence."
Mr Piercey said the requirements were there to ensure migrants made "maximum economic contribution here, add to New Zealand's overall skill base and do not compete for lower-level jobs with New Zealanders".
He said the agency was aware that some with unrealistic expectations were vulnerable to abuse by unscrupulous employers and others.
Since the Herald report about complaints to the Employment Relations Authority about E-Advance Limited, a company which helps international student graduates find jobs, more complainants have come forward.
It is alleged that the company has a "pay your own wage" scheme, where employees pay the company a lump sum on the understanding that it would be repaid as wages and taxes as proof of employment to help them gain residency.
One worker, originally from Sri Lanka, paid the company a job search fee of $10,000 and a further $5000 for broker and training services for his warehouse assistant administrator job.
Migrant workers union Unemig said fresh complaints are expected to be filed against the same employer this week.
The company has previously said it has done nothing wrong.
Graduate job search policy
*12 months for students who complete qualifications in NZ to find a job.
*Further visa granted under study to work if job relevant to qualification is found.
*A skilled job, generally managerial, professional or technical, is required for permanent residence.