Officials are investigating claims some restaurant workers are being paid just $4 an hour.
The Ministry of Business, Innovation and Employment is looking into complaints about an Auckland restaurant chain.
The Ministry's Labour Inspectorate launched an investigation after a significant number of individual complaints were received, with some workers alleging they get paid the "Indian salary'' of $265-a-week for up to 70 hours' work.
The allegations also stated workers did not get holiday pay or sick leave, were required to pay between $10,000 and $20,000 to secure their jobs while obtaining residence, and were kept in overcrowded accommodation for which illegal wage deductions were taken.
Labour Inspectorate Northern Manager David Milne says the investigation should serve as a warning to any business owners breaching employment laws.
"Labour exploitation is not welcome in New Zealand and it is totally unacceptable if people are subject to this type of alleged behaviour.
The Ministry will investigate and take action to the full extent available in law.''
The joint operation between the Ministry's Labour Inspectorate and Immigration New Zealand involved nine restaurants in Auckland.
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