The Prime Minister has announced Thursday 22 September, 2022 will be a National Day of Mourning to observe Her Majesty, Queen Elizabeth II, the full media release can be viewed here.

This results in a National Public Holiday with Public Holiday rules and entitlements applying.

The Fair Work Ombudsman holds relevant information for the following questions you may have:
general public holiday factsheet
not working on a public holiday
public holiday penalty rates

Information specific to NSW and the rules around public holidays can be found here.