A law change is being called for to allow the New Zealand Qualifications Authority to go undercover to catch student cheats and those who help them.
Police and the authority are looking into allegations that language website Assignment 4U offers university essays for a fee to overseas students, particularly Chinese students.
A newspaper says it used a fictitious student to buy an essay from what is claimed to be a commercial cheating service, but the authority says it can't use that approach.
In February this year, NZQA received allegations about Assignment 4U in an anonymous letter. However, it says the letter did not provide appropriate evidence and it could not investigate the business by trying to buy an essay, as that would be considered entrapment.
That is what the Sunday Star-Times did when the man behind the allegations contacted the paper recently.
NZQA wants to see the information the newspaper has obtained.
However, English New Zealand which represents 25 English language schools, says the authority needs to go undercover to investigate claims of academic cheating.
Chairperson Darren Conway says NZQA should have powers similar to those used to catch shops that sell alcohol or tobacco to underage shoppers.
"Their view is that they can't do it by means of entrapment. But I can't see what the difference is between going in and pretending to be a student and buying qualifications in order to ferret out that kind of unethical and illegal behaviour ... and the police sending in 14-year-old kids to try and buy cigarettes or alcohol."
Mr Conway said such an approach could have been used to investigate the Assignment 4U claims.
Tertiary Education Minister Steven Joyce said on Monday that Assignment 4U has been under the NZQA's scrutiny before.
"They were notified in 2009. They investigated at that time a similar if not the same company. And at that point, it was found it was a legitimate coaching service, rather than somebody ghost-writing assignments. That was their assessment at the time."
Mr Joyce said a new investigation would establish whether the so-called coaching service has moved into ghost-writing essays.
The minister said he is looking into why universities did not take greater action after they were alerted. He said neither the NZQA nor the universities told his office about the latest allegations until last Friday.
Former employee warned of 'cheating service'
A former employee of Assignment 4U says he told New Zealand institutions about the company.
The man, who wants to remain anonymous, says he worked for the company in 2007, writing essays that were then bought by international students. He says he wrote to several institutions warning them about the service, but had no replies.
Now based overseas, the man says he witnessed the cheating for himself while he was teaching in New Zealand.
He says many international students spend a lot of money coming to the country and will do anything to succeed and not let their parents down. "People are trying to find ways to get through the system as effortlessly as possible."
The Assignment 4U website says it provides counselling services to significantly improve the academic achievement of clients.