If you can't solve the problem on the job (with the help of your delegate and other members), then you can ask for assistance from the Department of Labour.
A mediator will work with you and your employer to resolve the employment relationship problem. Your union will help with the necessary paper work and deal with the Department of Labour to get a mediator. It's likely the mediation will also involve the workplace delegates and/or the union organiser for the site.
The role of the mediator is to help you and your employer to understand each other and to help you to reach an agreement. The mediator cannot make you or your employer agree to a solution.
If you and your employer agree to a solution, you can ask the mediator to sign the agreement. When the mediator signs the agreement, it becomes a settlement. Settlements are final and binding on you and your employer and can be enforced (in Court) by you or your employer.
If you and your employer cannot agree to a solution, you can both ask the mediator to make a decision about the problem. You and your employer must agree in writing before the mediator can make a decision. If you and your employer ask the mediator to make a decision, the decision will be a final and binding settlement and can be enforced by you or your employer.
If you and your employer cannot agree to a solution and do not agree to ask the mediator to make a decision, you can take your problem to the next step of the Mediation process - Employment Relations Authority .
Your union will talk through with you what is involved with taking your problem to the Employment Relations Authority .