One of the default rules (aka by laws in other places) in the ACT is:
<b>”Illegal use of unit</b>
A unit owner must not use the unit, or permit it to be used, to contravene a law in force in the ACT.”
So, an option, in principle would be to issue a rules infringement notice in accordance with s.109 then go to the ACT Civil and Administrative Tribunal seeking an order to enforce the rule. If you are confident that the short term leasing contravenes “a law in force in the ACT” then this catch-all rule gives you a route to address it.
I don’t know and have not checked whether there has been any testing of this in the Tribunal. You can search through published decisions at the Tribunal’s web site.
Alternatively, you can pay a lawyer to do this for you.
<b>”109 Breach of rules—rule infringement notice</b>
(1)This section applies if the executive committee of an owners corporation reasonably believes that—
(a)the owner or occupier (the <b><i>person</i></b>) of a unit has contravened a provision of the corporation’s rules; and
(b)the circumstances of the contravention make it likely that the contravention will continue or be repeated.
(2)The owners corporation may, if authorised by an ordinary resolution of the executive committee, give the person a notice (a <b><i>rule infringement notice</i></b>) requiring the person to remedy the contravention.
<i>Note</i> If a form is approved under s 146 for this provision, the form must be used.
(3)A rule infringement notice must state the following:
(a)that the owners corporation believes the person is contravening, or has contravened, a provision of the rules;<span class=”Apple-converted-space”> </span>
(b)the provision of the rules the owners corporation believes is, or was, contravened;
(c)details sufficient to identify the contravention;
(d)if the owners corporation believes the contravention is continuing—the period (which must be reasonable in the circumstances) within which the person must remedy the contravention;
(e)if the owners corporation believes the contravention is likely to be repeated—that the person must not repeat the contravention;
(f)if the person does not comply with the notice—
(i)the person commits an offence; and
(ii)the owners corporation may, without further notice, apply to the ACAT for an order in relation to the failure to comply with the notice.
(4)If a rule infringement notice is given to a person following a request under section 111, the owners corporation must, not later than 14 days after the day the request was received, tell the person who made the request that the notice has been given.”