What type of government does Australia and new Zealand have and who is it modeled after?

Australia and New Zealand both have parliamentary democracies and constitutional monarchies, with the British monarch as the ceremonial head of state. Their political systems are modeled after the British parliamentary system, featuring a bicameral legislature, an elected Prime Minister, and a system of responsible government. In both countries, the Governor-General represents the monarch and performs various ceremonial duties while the Parliament holds legislative power.