The New Zealand Qualifications Authority (NZQA) has been investigating alleged unlawfulness at 14 private education providers over the past two months, with 11 of them relating to international students.
Two of those providers have had statutory action taken against them, resulting in sanctions.
An investigation involves NZQA taking action to follow up known, self-disclosed, suspected or alleged non-compliance with the Education Act 1989 or NZQA rules.
There are around 200 private education establishments (PTEs) operating in New Zealand, with many offering courses to international students.
A spokesperson for NZQA says its powers were bolstered recently.
"Since July 1, 2016, NZQA has started investigations of 12 providers (of which two investigations have now closed), and taken statutory action (sanctions) against a further two providers," the spokesperson says.
It comes amid growing concern for the international education sector, which last week saw revelations of corruption amongst agents in India.
Tertiary Education Minister Steven Joyce told The Nation NZQA's investigations are normal.
"There's always a whole lot. We do about 30 to 40 a year. There's something like 600 providers internationally, including schools and PTEs and universities and ITPs. We always have a number under investigation," he says.
"We always have that many. There's always things that are going on which we would all prefer not to."
Labour leader Andrew Little isn't buying Mr Joyce's explanation, and believes he should be taking it far more seriously.
"That's seriously out of whack, in proportions alone. And it tells you the Government has got to do way more than it's doing at the moment in hoping the problem's just going to go away, because it isn't," he says.
He claims the Government has allowed the sector to grow at an unsustainable rate, without the right regulatory oversights. He fears the fallout of affected students leaving New Zealand.
"If they leave New Zealand without a qualification, having forked out or borrowed thousands of dollars, and go back to their home countries unhappy, that's going to destroy our reputation and it will ruin the industry forever."