The investigation began in Australia last year after the murder of two FBI agents in Florida in 2021 who were investigating child abuse in the US, police say.

The operation, dubbed Operation SpecTor, involved multiple law enforcement agencies and was conducted across the US, Europe, and South America.

A banner plastered across Genesis Market's site late on Tuesday said domains belonging to the organisation had been seized by the FBI.

The latest release on the dark web follows progressive uploads, including records of customers' mental health and alcohol use, that began after Medibank said on Nov 7 it would not pay a ransom.

Fears of catching the virus have driven a sharp increase in online shopping, which in turn has led to a major rise in delivery fraud in the second year of the pandemic, Europol said in its annual cybercrime report.