Bhardwaj had also threatened to have the employee's visa terminated and told him the rate of pay would not be changed.
Peter Devoy, INZ's assistant general manager, described the case as "significant exploitation" and said the fine and sentence sent a strong deterrent message.
"The exploitation of migrant workers by paying them less than the minimum wage, forcing them to work excessive hours and threatening their visa status - such as happened in this case - is unacceptable and won't be tolerated by INZ," Devoy said.
"This is happening all too often in NZ, and we won't stand by and let it happen. Where there is evidence, we will investigate and prosecute."
People who believe they are being exploited are encouraged to get in touch with the authorities.