Six businesses were served Improvement Notices, one closed and one has been referred to the Employment Relations Authority for penalties.
Two businesses were required to pay arrears as high as $25,460 and $28,758.
Ministry of Business Innovation and Employment labour inspectorate regional manager Kevin Finnegan said the exploitation of migrant workers was unacceptable.
"MBIE takes these breaches very seriously and is working proactively to crack down on it through joint compliance operations targeting sectors and at risk workers across New Zealand.
"Failure to produce and maintain accurate records was a major contributor to non-compliance, with a total of 20 breaches identified.
"Without accurate time and wage records, the employer cannot demonstrate they are providing their employees with the correct entitlements," he said.
There were penalties of up to $50,000 for any employer who breached employment law, he said.
Ministry of Business Innovation and Employment encouraged anyone in this situation, or who knows of anyone in this situation, to call its contact centre on 0800 20 90 20.