My boss expects unpaid overtime on a salary, is that allowed?

It depends on your employment agreement. Under the Employment Relations Act 2000 and the Minimum Wage Act 1983, your employment agreement must include a reasonable hours provision, and the salary must still equal at least the minimum wage for all the hours you actually work. If your pay divided by the hours you work falls below the minimum wage, you are underpaid. For hours beyond a reasonable amount, the Act requires that additional work is compensated where the agreement provides for it, and an agreement should set out the availability provisions and any compensation for them. Keep a record of your hours, then raise the issue with your employer in writing. MBIE's Employment Services can investigate, and the Employment Relations Authority can order arrears for up to six years.