justsaying – in NSW Sect 80A of the Act automatically restricts Executive Committees’ expenditure to Items against which a Budget has been determined at the last AGM, and further restricts any expenditure on any Item that’s in excess of that budgeted amount to 10%.
So at the next AGM, when the compulsory Motion arises about whether or not your Owners Corporation wishes to ensure “that any matter or class of matter is to be determined only by it at a General Meeting”, a simple majority vote NOT to remove the Sect 80A restriction and an insistence on compliance with the provisions of Sect 80B for any proposed expenditure >$30K should get the outcome that you require.
One last modicum of advice – when it comes to budget time try to ensure that catch-all Items such as “General Repairs” into which almost any expenditure can be dumped are avoided. If you know on what specific items expenditure is planned in the coming year, then insist that they’re listed as specific items with a corresponding budget, and if you don’t know at the time when the Agenda is distributed, then find out before the Meeting so it can be nailed-down as an amendment to the proposed budget at that forum.