The Human Rights Act 1993 and its amendments make it illegal to discriminate against anyone on the basis of their:
In addition, employers may not advertise in a way that suggests that they will discriminate on any of those grounds.
Complaints under the Human Rights Act go to the Human Rights Commission for investigation. In the first instance, the Commission will try to mediate an acceptable resolution between the complainant and the respondent. If that fails, the Commission may issue a variety of orders and (very rarely) award damages.
The Employment Relations Act 2000 also prohibits discrimination on these grounds. If an employee considers that they have suffered discrimination, they may take action against their employer as a personal grievance in accordance with the provisions of that Act. However, if an employee does this, they cannot also complain under the Human Rights Act.