I would have thought that the partition would require several different types of approvals:
(1) planning and construction approval by Council (see State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 [Subdivision 26 s252(b)], and
(2) approval by the OC and
(3) a By-law created – then approved at a General Meeting – then Registered.
From my reading of the Code it seems that the partition is not classified as an Exempt and Complying development. Subdivision 26 Minor building alterations (internal)
The standards specified for that development are that the development must:
(aa) not be an alteration to a food preparation area in food and drink premises, and
(a) if it is the replacement or renovation of a deteriorated frame member—be of equivalent or improved quality materials, and
(b) not include a change to the configuration of a room, whether by removal of an existing wall, partition or other means, and
(c) not cause reduced window arrangements for light and ventilation needs, reduce the size of a doorway or involve the enclosure of an open area, and
(d) not affect the load bearing capacity (whether vertical or horizontal) of a building, and
(e) not include a change to the fire resisting components of, or interfere with the entry to, or exit from, or the fire safety measures contained within, a building, and
(f) if it is the installation of new or replacement insulation material in a dwelling, it must be in accordance with Part 3.12.1 of the Building Code of Australia.