The Australian Federal Police is investigating reports Australians' personal Medicare details are being accessed and sold on the dark web, an apparent breach that has been labelled an "internet catastrophe".

According to a Guardian Australia report, an online vendor can pull up the full Medicare card details of any Australian on request — and is selling them for around $30 each — indicating a security hole somewhere in the health system.

Human Services Minister Alan Tudge said the government was taking the matter seriously.

The sales are reportedly listed on an undisclosed dark web marketplace, in which the vendor claims to be "exploiting a vulnerability" in order to run software that pulls the data. The vendor calls it "the Medicare Machine".