From a regulatory point of view it makes no difference who the lender is, it could be a bank or a private investor lending out their SMSF, the same rules apply. What determines the regulation of loans in Australia is the borrower and the loan purpose. Those two factors determine whether the loan will be regulated or unregulated by the National Credit Code.
Private lenders do not generally hold credit licenses, nor is it usually commercially viable for them to do so. For that reason private lenders cannot loan on National Credit Code regulated loans.
If a loan is made to a company borrower then the loan is not regulated by the National Credit Code. Bransgroves Lawyers recommend against entering loans where a company borrower has been created simply for the purpose of avoiding the code. This is because there have been judicial decisions where this has been found to be a minor part of overall circumstances that gave rise to a finding of unconscionability. That said, where the loan is fully commercial in nature then Bransgroves Lawyers find no legal or ethical impediment to the lender requiring the loan to be made to a company.
It is not unusual to find a stable broker who holds a credit license for their bare trustee. This allows national credit code regulated loans to be written with private mortgage investors.