The nature of the proposal being assessed and the permit triggers will determine if an application can be split. An application cannot be split when approval of one part of a proposal necessitates consideration and approval of another part. Conversely an application could be split when the individual parts can be independently considered and approved.
For example, where a planning permit is required to extend a shop and reduce car parking, approval of the proposed extension is dependent on approval of the car parking reduction. Similarly the car parking reduction will involve considering the additional floor area proposed. Each component of the application cannot be assessed without considering the other. The application cannot be split.
However, an application could be split when the individual parts can be independently considered and are not interconnected. For example, in a Heritage Overlay where a planning permit is required for a fence and house extension, approval of the fence is not dependent on approval of the house extension. One may be assessed without considering the other. The application could be split.
Source VicSmart Planner and Practitioner Guide by the State of Victoria
If an application were to be split the applicant would need to submit all necessary information with each application and pay a fee for each application.