In Australian family law, grandparents do not have an automatic right to spend time with their grandchildren. This situation can arise due to the divorce or separation of their own children. However, grandparents may bring an application before the Court by reason of being a person concerned with the care, welfare or development of the child.
Where it is considered to be in the child’s best interests to maintain a relationship with his or her grandparents (in circumstances where the parents of that child are not permitting contact), then the Court may make an order for the grandchildren to spend time with their grandparents.
For more details click on Grandparent visitation rights to grandchildren