Normally, if there are court orders already in place there will be an order in relation to relocation. You should check the last set of Court Orders for this. If this is the case, then if a parent wants to move a considerable distance away, they must obtain permission from the Court.
The Court may not necessarily grant permission as they may not be satisfied that moving away from one parent is in the best interests of the child.
You can oppose the application to stop the other parent from relocating and tell the court why you think the child should not be relocated.
If the other parent takes your child without discussing it with you, you can apply to the court for a Recovery Order to return the child to where they normally live. A Recovery Order can be made even when there are no parenting orders in place.
If you already have Court Orders in place and they prevent a parent from relocating, then the other parent will contravene the Order if they relocate. You can then apply to the Court to enforce the current order through the Federal Police.