Wikipedia
In Australia, a lieutenant-governor is a standing appointment for a deputy governor of a state, who acts in place of the governor if the governor is unable, unavailable or unwilling to act.
Constitutionally, Australian state lieutenant-governors, administrators and chief justices of state supreme courts are normally separate offices. However, in many states, such as New South Wales, the Chief Justice of the Supreme Court is also the lieutenant-governor. In 2001, the Constitution of Queensland was amended to restore the office of lieutenant-governor in that state. When a state governor dies, resigns, or is absent, an administrator, or acting governor, wolLieutenant-governor". The state lieutenant-governors/administrators have no standing powers but stand ready to take up the governor's role.
In some states, there is also a standing deputy governor, who can exercise only the powers which the governor delegates to him or her.