The strata committee should arrange a report into Work Health and Safety from a reputable safety company (eg “BIV” is the biggest company doing this), to advise on the risk and how to avoid it. This determines if the risk is significant. A hedge takes time to grow, so a temporary solution may be needed until it reaches a good height. Providing a WH&S report is normally an agenda item for each strata AGM.
Otherwise a consulting engineer, knowledgeable about safety, could be engaged to provide potential solutions.
This is normally not a thing you should guess at, unless the solution you come up with will clearly mitigate the problem. I think a drop of 2.4m is high, and the building code may have some specific requirements, like a fixed balustrade. It will also depend on if the drop is on lot property, or common property, and who has access to the area. Get expert advice!