I assume the poster in not in the ACT (from referring to SC rather than EC). I am sure JT’s advice is correct for NSW.
Just to note some state differences: In the ACT (UTMA Sch2.4), “the executive committee of an owners corporation may approve an application by a member of the corporation to use the common property if— (a) the use applied for is minor; and (b) the use will not unreasonably interfere with the reasonable use and enjoyment of the common property by other members of the corporation.” An awning extending over common property is given as one of the examples.
Regardless of the approval mechanism, conditions on approval may be applied such as requiring the use of a preferred colour and design (to maintain the appearance of the common property and thereby ensure that enjoyment of the common property is not interfered with) and requiring the unit owner (and any future owner) to undertake any necessary maintenance, to keep it in a good state of repair, and to restore the common property if the awning is removed.