In Victoria, swimming pools and spas with a water depth of more than 300mm (30cm) require a compliant fence to be installed.

A building permit must be obtained before you install a new pool or spa, start construction on a new pool, spa or barrier or make alterations to a pool, spa or barrier (if not maintenance related). A building permit can be obtained via a registered building surveyor (private or municipal).

See the attached information sheet provided by the Victorian Building Authority which provides clear information on pool & spa fence compliance

Pool & Spa Fence Compliance Information Sheet

Source: Victorian Building Authority