A carport or garage requires building certification (approval) before construction begins. This includes DIY kit type structures, because Cairns is in a cyclonic region as specified in the Building Code of Australia. Because of this, construction detailing and tie-down requirements are more stringent than in non-cyclonic zones.
You will need to engage a building certifier to assess if your proposed garage, carport or shed complies with building regulations and standards.
If you are also adding an extra driveway, that work will require Development Approval from Council (see Driveways & crossovers).