A Privacy Victoria spokesperson told Computerworld Australia that the Commissioner has asked the Transport Ticketing Authority (TTA) for a briefing on the matter and has requested a response by 22 August.

Victorian Public Transport Users Association (PTUA) president, Daniel Bowen, said the Myki ticketing problem dates back to 2010 when the system was introduced to Melbourne.

"These receipts affect all customers who use Myki vending machines on stations, major tram stops and bus interchanges to top-up their cards, and paying via Eftpos using a debit or credit card," he said.

The ticket vending machine will ask if a receipt is wanted, and will print a receipt even if the customer presses the decline button, according to Bowen,

The PTUA has posted a which show that nine out of the 16 digits of the customer's debit or credit card number is visible along with the expiry date, and full name.