In Australian politics, a leadership spill is a declaration that the leadership of a parliamentary party is vacant, and open for re-election. A spill may involve all leadership positions (leader and deputy leader in both houses), or just the leader.
A leadership spill occurs when a member or members of the parliamentary party feel that the leader is taking the party in an undesirable direction or is simply not delivering on their promises to those who elected them, and does not have the numbers to back his or her position. A spill can be initiated by the leader themselves, usually to ensure a fresh mandate to quell dissenting voices in the party.
A leadership election may result in a new leader, or may confirm the status quo. If the party in question is in government, the election of a new leader will result in a new Prime Minister, Premier or Chief Minister; if the party is the opposition, the election of a new leader will result in a new Opposition Leader.