Policing rogue employers and education providers is a top priority for new immigration minister Iain Lees-Galloway.
Mr Lees-Galloway, who is also the Workplace Relations and Safety Minister, said he wanted to double the labour inspectorate so it could better investigate allegations of immigrants being exploited.
Enforcement staff had told him they were only able to look into two-thirds of the cases they wanted to investigate, he said.
He wanted to weed out poor companies in the international education sector and focus on bringing in skilled migrants rather than cheap labour, he said.
"There are rogue employers out there who are getting away with very poor practices, and it just lets the side down.
"It's important from the view of looking after people, but it's also important from the view of looking after New Zealand's international reputation."
Mr Lees-Galloway said he has asked officials to review visa categories and look at extending licenses for immigration advisers to those providing student visa advice.
He said forecasts based on the changes they want suggested a reduction of 20,000 to 30,000 immigrants, but there was no target.