Can I discuss my proposed development with my neighbours before lodging the DA?

Yes. You can discuss the proposal with neighbours before the DA is lodged, and doing so can be useful for identifying concerns early.

You might show them the proposed site plan or elevations and discuss matters that could affect them, such as privacy, building height, setbacks, overshadowing or construction access. This gives the design team an opportunity to consider relevant concerns before the plans are finalised.

However, speaking with neighbours beforehand does not replace the formal public notification process. Once a DA is lodged, public notification is a formal part of the assessment process and neighbours may still make a representation on the application.

Example: Before lodging a dual-occupancy DA, you could show the adjoining owner the proposed plans and discuss the location of upper-floor windows. If they raise a reasonable privacy concern, the design could be reviewed before lodgement.

Reference: ACT Planning, After you Apply - https://www.planning.act.gov.au/applications-and-assessments/development-applications/after-you-apply