The court heard how the then 24-year-old was paid A$200 cash for his first few days of work in 2012 but then worked six evenings per week for the next four months without receiving any pay.
He said he was reluctant to complain because he had hoped Mackenzie's company would sponsor him on a work visa. When he sent a text message saying he was sick and would provide a medical certificate the next day, Mackenzie replied saying, "Don't come back."
He then sent a series of follow-up messages saying, "Don't expect any sympathy ... pls don't my lawyer sue you for defamation of my character. Pls return key today" and "If you don't answer I will ring the police and say you possession [sic] of my keys to my business and I want them bak [sic]. They will come to your house and arrest you for theft."
The worker lodged a complaint with the Fair Work Ombudsman, which commenced an investigation and then legal action. The court found Mackenzie and his company guilty of underpayment, providing false records to Fair Work inspectors and of taking adverse action against an employee for accessing a workplace entitlement.
"The conduct in relation to the termination of employment of [the worker] is, in the court's view, more egregious because of the manner in which it was carried out," Judge Lucev said.
"The ongoing denials of liability, and the unsubstantiated assertions concerning the conduct of [the worker], together with the sheer belligerence exhibited by Mackenzie before the court, renders this a case in which specific deterrence is a greater factor in fixing a penalty which specifically deters conduct similar to that which has occurred in this case, in the future.
"Mackenzie went so far as to suggest that [the worker] might have somehow had an involvement in events, or events which led to, the burning down of the restaurant, an assertion which was simply not the subject of any evidence whatsoever."
Judge Lucev described the conduct as "egregious", saying the "deliberateness of the contraventions" was "plainly proven". "Mackenzie's attitude as evidenced at the penalty hearing is cause for serious concern in relation to any possible future employment by him or by any company with which he is associated," Judge Lucev said.
Fair Work Ombudsman Natalie James said the case involved "shameful exploitation of a vulnerable worker" and Mackenzie's conduct "thoroughly deserved the strong criticisms it received from the court".
"Migrant and overseas workers in Australia are lawfully entitled to the same minimum wages and conditions as any other worker," James said in a statement.
"There is no place in Australia for this kind of highly exploitative and callous treatment of a young, overseas worker — and we will not hesitate to pursue any business operator who seeks to engage in this type of conduct."
