What happens if a senator resigns or dies before his or her term expires?

When a casual vacancy occurs in the Senate, on the resignation or death of a senator, a new senator is appointed by the parliament of the state which the former senator represented. If the state or territory parliament is not sitting, an appointment can be made by the Governor of the state (or in the case of an Australian Capital Territory senator, the Governor-General, or the Administrator in the case of the Northern Territory) and the appointment is confirmed by the parliament when next it assembles. In order that the Senate continue to preserve the representation of parties in the Senate as determined by the electors, the new senator must be of the same political party or group as the senator he is replacing. It is a matter of contention whether this means that the appointee must be the nominee of the political party or whether it suffices that he or she is a member of that party. [Senate Brief No.  more