The Reserve Bank of Australia's computer systems have fallen victim to cyber hacking in at least two sophisticated online attacks.
Documents released by the RBA show the central bank was the victim of a "highly targeted" email attack in November 2011.
It is understood the RBA was also targeted in the lead-up to the G20 meeting in Cannes earlier that year, though it is not known what, if any, information was stolen.
An RBA spokeswoman could not confirm claims published in the Australian Financial Review that "Chinese-developed malicious software" had been used in the G20 incident.
Chinese cyber hacking is increasingly being acknowledged as a significant threat by Western governments and major companies.