NZ First leader Winston Peters says thousands of international students are the victim of false promises.

Winston Peters has slammed the Government's "exploitation" of international students.

The NZ First leader, known for his colourful descriptions of Government ministers, says Joyce, the Minister for Tertiary Education, is aware international students are being "exploited" - as is his department.

"If you bring people into the country, force them to get low wages on the basis that they will be able to stay, give them a work permit as well, and they can't stay because of the illegality they're involved in - then it is a form of people trafficking," Peters said.

ROBERT CHARLES/FAIRFAX NZ Tertiary Education Minister Steven Joyce says international students in New Zealand is a "good news story overall''.

International students are in the spotlight after an Immigration New Zealand investigation this week revealed widespread use of fake documents by Indian education agents to get students into New Zealand.

READ MORE:

* Widespread fraud found among education agencies

* Auckland's Indian students frustrated by lack of support

* 550 students deported from New Zealand since 2010

* Warning of 'education trafficking' scams hitting New Zealand

Peters also had another choice word for Joyce as he accused the minister of "human trafficking".

Joyce dismissed Peters comments as "typical Winston exaggeration" that would be expected after 40 years of opposition to immigration.

"It is actually a good news story overall. We've got about 125,000 students generating three and a bit billion dollars in income for New Zealand.

"We just have the occasional agent and the occasional provider that doesn't do things properly and we have to sort that out," Joyce said.

Both Peters and Labour leader Andrew Little described international students as a "cash cow".

Peters said thousands of international students had been promised they could stay in New Zealand, "which is a false promise made at the time of the application".

Little said there's no doubt a lot of secondary schools would "struggle to make their budgets balance" without international students.

"I don't think it's a question of there being too many. The main thing is the education we're providing them and whether it's a good quality and making sure we're providing accommodation and so on," he said.

But Joyce said the Opposition leaders comments showed "once again they'd rather close New Zealand down than do things that generate income for us".

"If our friends Mr Little and Mr Peters don't want the income then that's fine. It's the same as they don't want a whole lot of other industries that generate income and jobs for New Zeland."

The Immigration New Zealand report revealed 44 Indian agents had been involved in fraudulent applications in the March 2016 year alone.

In total, 57 agents had been identified as using fraudulent methods - some using fake documents for almost all of their applicants.

According to Statistics New Zealand, 9800 people arrived from India on student visas in the year to March 2016.