This is pure speculation, but on the face of it, the Myki card appears to be equivalent to any bank-issued debit or credit card.  If that's true, the Myki card system may-well be in contravention of the banking laws of Australia.

Allow me to state in advance, this piece is based on assumption and common sense; neither of which has any standing in legal processes; however please hear me out; remembering that I am not an expert in this area, simply a purveyor of common sense.

As far as can be established, the Myki is a stored value card; one can add and remove money from it.  If that were not true, one would not be able to get a refund from one's card in a process that does not involve the use of the card for the stated purpose (public transport).  Never mind the totally unconscionable fee of $9.80 for recovering one's own money.

Some time ago, the Minister in charge of the Myki project stated very clearly that the card would be available for small-value transactions from a variety of vendors - presumably ones geographically closely related to transport, such as railway station kiosk vendors.  

Late in the saga, this functionality was dropped from the final deliverable.  It is not possible to determine if it was too difficult or whether (even then) the legal issues were identified.

Right now, we have an organisation; is it Kamco?  Is it the Transport Ticketing Authority?  Is it someone else?  We have someone holding potentially millions of dollars of consumer's funds in the expectation of future use on Melbourne's trains, busses and trams.  Surely this money would be invested in a variety of short-term money market instruments and contracts.

Does this make the responsible body a financial institution under the banking laws of this country?  I don't know.  But if nothing else, it certainly means that whoever the responsible body is, ought to have some very rigorous controls regarding financial transactions to obey.

Right now, the Myki's critical websites, the Myki Users Group for instance, contain a large number of transactional complaints that may-well be of interest to Australia's banking Ombudsman.

Time will tell what becomes of this.