There are three main branches or elements of government: legislative, executive and judiciary. Each has its own powers and responsibilities and each, to some extent, is separate from the other. But each also has some power or authority over the others. No one branch can control all power in a democratic system. This is referred to as the Separation of Powers. The powers and roles of the institutions of government for New South Wales are set out in The Constitution Act 1902 or the Constitution of New South Wales.

The Legislature
This is the law-making body.
In New South Wales this consists of the Parliament, made up of two Houses
(the Upper House) or Legislative Council, and the Lower House or (Legislative Assembly) together with the Governor of New South Wales.
As well as law-making, Parliament represents the people (through elections) and determines the Government (the party with an elected majority in the Lower House).
It also provides a check on the activities of Executive Government.

The Executive
This is made up of the Premier and Cabinet or Ministers.
Each Minister is responsible for one or more government departments or agencies which carry out the activities of government.
The Ministers are appointed from amongst the majority party in Parliament and remain members of Parliament and are responsible to Parliament.
The Ministers develop, implement and administer government policy.

The Judiciary
This is made up of independent judges appointed to a system of courts, the highest being the NSW Supreme Court. There are also federal courts and the highest court for the whole of Australia is the Commonwealth High Court. Judges are appointed by Executive Government but cannot be removed except by a Parliamentary process. Judges interpret the laws
- in the highest courts they can even disallow laws which are found to be unconstitutional. They ensure that the law is applied fairly to all.