More than 50 workers at eight sushi bars in Whangarei will be paid a total of $71,000 in holiday pay as a result of an investigation by the Labour Inspectorate.
The inspectorate's regional manager, Kevin Finnegan, said investigations revealed serious breaches of employment laws.
They included failing to keep time and wage records, provide employment agreements, pay minimum wages or holiday pay.
All of the businesses, which could not be named for legal reasons, employed migrant workers.
Mr Finnegan said employers who breached employment law could face penalties of up to $50,000 for an individual or more than $100,000 for a company.