The Westminster System comprises:
The Westminster system. (2021, December 15). Senior Executive Fundamentals. https://sef.psc.nsw.gov.au/nsw-government-context/the-westminster-system#key-components
Australia's political system is based on the Westminster system. Westminster is the name given to the system of parliamentary democracy used in countries such as Britain, Canada, Australia and New Zealand and is named after the area in central London where the Parliament of the United Kingdom is located. All state and territory parliaments in Australia follow the Westminster system.
The essential features of the system are:
There are three recognised branches of government in the Westminster system: the legislature; the executive; and the judiciary.
from http://www.parliament.act.gov.au/learn-about-the-assembly/fact-sheets/westminster-system