Officials from the Ministry of Business, Innovation and Employment have been tasked with researching exploitation of temporary migrant workers in a bid to stamp it out.

Immigration and Workplace Relations and Safety Minister Iain Lees-Galloway said many migrant workers, especially those on temporary and student visas, were particularly vulnerable to exploitation.

"Migrant exploitation takes many forms, including workers not getting paid properly, working excessive hours or in unsafe conditions. Crucially, far too many migrant workers do not feel empowered to speak up or seek help when they are being subjected to unfair conditions," Lees –Galloway said in a statement.

Migrant exploitation spanned "ignorant non-compliance" with minimum employment legislation, through to forced labour and people-trafficking.

Ministry of Business, Innovation and Employment (MBIE) officials and University of Auckland researchers would speak to migrant and international student groups, unions and businesses in a bid to better understand worker exploitation.

The research would identify gaps and opportunities to reduce exploitation and make recommendations on potential regulatory, policy or operational changes, including labour market protections, to reduce exploitation.

Lees-Galloway said the review would take some time and he expected to make decisions next year.

In the meantime, other initiatives underway included an increase in the number of labour inspectors' changes to post-study work rights to help reduce the risk of international student exploitation, he said.

Last month an MBIE investigation targeting Chorus contractors found nearly all were breaching employment standards.

Violations include "volunteer" work or extended training periods without pay, plus less than minimum-wage pay.

Workers in other industries including hospitality, retail and the sex industry have also been found to have been exploited.