If a wall is part of the structure supporting the building, then it is deemed to be a retaining wall. Removing or altering a retaining or supporting wall is considered to be a structural alteration. You will always need a building permit for any structural alterations to a building.
You may also need a soil report to successfully apply for your building permit. Please contact Council's Building Department on 9518 3555 for more information.
Planning permits for retaining wall renovations are not essential, unless:
If you have encountered suspected asbestos as part of your renovation, please see the following section before work continues: Encountering Asbestos.
More information: Asbestos in Victoria (www.asbestos.vic.gov.au)