The rules of the international game of football are determined by FIFA. Called the Laws of the Game (LOTG), they define the game as played around the world. The Football NSW Referees Resources webpage has compehensive information.
The LOTG allow for local Football Associations to vary the rules in accordance with local conditions and development of junior and elite players.
Modifications to the LOTG for GHFA matches are contained within the GHFA Rules& By-Laws.
Modifications to the LOTG for NWSWF matches are contained within the NWSWF Rules& By-Laws.
Since 2008, matches for Under 6 to Under 11 age groups have undergone significant changes. The Football Federation Australia (FFA) based Small Sided Games (SSG) concept encourages skills and participation in the youger players. Note that the local associations may vary the SSG rules to suit local conditions (see GHFA SSG Rules)
Additional information on the LOTG and how they are managed by match officials can be found at Gladesville Hornsby Football Referees Association.