Each political party represented in the Federal Parliament elects leaders in each house.
Just as the government is decided in the House of Representatives, so the parties elect their leaders and deputy leaders from amongst their representatives in the House. If the party is not represented in the lower house, its leader will be chosen from amongst its members in the Senate.
These tables are correct as of September 21, 2015. They take account of the change of prime minister on September 15 and consequent changes.