Section 139(2) of the Strata Schemes Management Act prevents an Owners Corporation from restricting whom a lot can the leased to… “s139(2) By-law cannot prevent dealing relating to lot – No by-law is capable of operating to prohibit or restrict the devolution of a lot or a transfer, lease, mortgage or other dealing relating to a lot.”
The person who is leasing the parking bay IS a resident in the building, and must be treated equally to all other residents. That does lead to the curious situation, that their visitors can also, in theory, use your visitors parking spots!
Still, they must obey your building’s by-laws. Make sure they are registered on the strata roll, and that a section 258 Notice has been filed by the owner/agent to record this, which is mandatory. In a practical response, you could talk to the owner of that bay, and see if they can rent it instead to someone living in a Unit in your building, who wants a 2nd parking bay? Often the owner is renting the parking spot informally, and requiring them to record the leasing details under s.258 will make them realise they need to draw up a lease, and disclose the income for tax purposes.
Don’t let the owner shrug off the s.258 Notice, if they say that they don’t have a written lease, and don’t want to arrange one. Their parking tenant must be on the strata roll, or else they are not a resident, and if not a resident then they can’t park in the garage. The s.258 Notice must be provided within 14 days of the lease commencing, too. The tenant can file the s.258 Notice themselves. But you can refuse to allow the person to park there until the roll is updated, and s.139(2) assumes the owner then follows the other requirements of the Act.
I think you could amend your by-laws to only allow visitors to residents who are from the residential lots to use the visitors bays. There are other exclusions in the Act for owners of utility (ie carpark) lots, and a properly drafted by-law would probably be legally enforceable. In fact, you could probably act on that assumption, and once the parking leasee is on the strata roll, you could issue a by-law breach notice, on the basis that he is not entitled to allow his visitors to use the visitors parking bays, because he is only leasing a carparking bay, and car parking bays do not normally get visitors. But check the wording of your parking by-laws.