International students returning from China after their holidays are being denied entry to New Zealand and having their visas cancelled because they have not made good progress on their courses.
Border control officers have interviewed 32 student visa holders at Auckland Airport, and 14 were denied entry and had their visas cancelled.
Another two students were stopped from boarding their flights in China.
One diploma of business student from Prime International College was put on the next flight home because "he failed to make sufficient progress on his course" and another from the New Zealand Institute of Studies was refused entry because he could not speak or write proper English during the interview.
"The main reason for the students being denied entry was doubtful bona fides, and Immigration was not satisfied that they were coming to New Zealand for the stated purpose of study," said agency spokeswoman Rachel Purdom.
"There was also evidence that several students were failing to comply with the terms of their visas."
To comply with the visa terms, students must be able to show that they are passing their course and meeting their attendance requirement, Ms Purdom said.
The students stopped at the airport were identified through the agency's screening and profiling systems as not meeting the requirements for entry.
About 24,000 student visas are approved annually for China nationals, and nearly 3500 were approved between November and January.
"New Zealand is recognised worldwide as a high quality provider of international education and warmly welcomes genuine students from China, which comprises New Zealand's biggest market for international students," Ms Purdom said.
"They must, however, ensure that they comply with the terms of their visas."
NZ Institute of Studies operations director Peter Chou said at least two students from his institute had been stopped from entering New Zealand.
Mr Chou said the agency's action has brought New Zealand's visa system into disrepute, as international students were now questioning the worth of their visas.
"They are not illegal ... they are holding valid student visas and for Immigration to deny them entry is wrong and unfair," he said.
"They were approved by Immigration to study here, and the least they should be allowed to do is to study until the date of expiry on their visa."
Prime marketing director Vincent Hii said the college was "very selective" about the students it enrolled, and he was surprised that its students were among those who had been turned away.
"We are tough about them meeting visa obligations and improving their academic standards, so this is totally unexpected," Mr Hii said.
An immigration adviser who did not wish to be named said he had received inquiries from some of the barred students wishing to appeal or take legal action.
In 2011, nearly 300 student visas approved in Immigration's Beijing office were found to contain fraud.
Of the 245 who came to New Zealand, 56 have left the country and 154 remain in it unlawfully.
Immigration is assessing 28 applications, and 35 have been granted further visas.