Unless there is some quirk in NSW law, I expect it is like in the ACT. Here, if the Act specifies that a particular decision requires a resolution of the owners corporation (OC), that can only be done at a general meeting of owners. For many decisions, an ordinary resolution is sufficient (simple majority of the meeting). Some particular types of more serious decisions require higher resolution standards such as a special resolution (a majority in favour and fewer than 25% opposed in NSW) or an unopposed resolution or a unanimous resolution.
The powers of the EC are limited to functions of the OC that don’t specifically need a general meeting resolution. Even then, if the OC has made a decision, the EC is bound to follow the OC’s direction. Eg. the OC might resolve that the EC should follow a set of guidelines when acting in some area within its powers. An OC does not have the power to delegate a decision to the EC if the Act says the decision must be a general meeting resolution. In the ACT, the EC’s functions are described as follows. I expect NSW has something similar.
(1) The executive committee of an owners corporation exercises the functions of the corporation.
(2) Without limiting subsection (1), the executive committee’s functions include the following:
(a) developing matters in relation to—
(i) the common property; and
(ii) the strategic affairs of the owners corporation;
(b) submitting matters developed under paragraph (a) to the owners corporation for consideration;
(c) monitoring the owners corporation’s financial performance;
(d) approving the annual financial statements and budget for presentation to the owners corporation at the corporation’s annual general meeting;
(e) supervising the treasurer, secretary, manager (if any) and communications officer (if any);
(f) carrying out the decisions of the owners corporation made at general meetings.
(3) The executive committee must exercise its functions—
(a) as the corporation directs by resolution at a general meeting; or
(b) in the absence of a resolution—as the committee considers appropriate.
<i>Note </i>The resolution required under s (3) (a) is an ordinary resolution, unless the Act provides that the resolution should be a special, unopposed or unanimous resolution—see sch 3, s 3.14 (Decision-making at general meetings).