The Reserve Bank of Australia (RBA) revealed Monday that its computer networks were hacked but no data was lost or compromised, while media reports claimed some of the machines were infected by malware developed in China.

The central bank said that none of the systems were compromised in the November 2011 cyber attack and no information was leaked as elaborate security arrangements checked the spread of viruses.

"As reported in today's media, the Bank has on occasion been the target of cyber attacks," the RBA said in a statement on its website.

"The Bank has comprehensive security arrangements in place, which have isolated these attacks and ensured that viruses have not been spread across the Bank's network or systems. At no point have these attacks caused the Bank's data or information to be lost or its systems to be corrupted."

Documents released under the freedom of information provision showed a malicious email attack occurred Nov. 16-17, 2011, on multiple computers in the RBA network. All the systems were identified and removed from the network subsequently.

The Australian Financial Review reported Monday that multiple computers of the central bank was infected by malware seeking intelligence information and one of the viruses was a Chinese developed spy software searching for information on sensitive G20 negotiations.

A Reserve Bank official confirmed the G20 virus to Agence France Presse (AFP) and said it was confined to only "a few" computers. The official did not say what information was stolen or who was targeted, and would not confirm the Chinese connection, the AFP reported.

However, the bank’s statement Monday was silent on the media report that said the infected malware was Chinese-developed but said it takes the threat seriously.

RBA, in the wake of the cyber attack, has initiated several steps to update its defenses against malicious infection with scanning and auto-blocking of hyperlinks in emails.

The malicious software was embedded in a hyperlink of an email sent from a "possibly legitimate" external account purported to belong to a senior bank official. The email with subject line “Strategic Planning FY2012″ was sent to several RBA staffers and had legitimate email signature. Six people opened the email containing virus compromising their work stations, Reuters reported.

The cyber attacks against banks and other prominent financial institutions have become common and China has been blamed frequently for the attacks.

However, China has refuted the allegations and has been blaming the U.S. for the cyber attacks. China had termed the U.S. as the largest source of hacker attacks targeted against it.

In February, the Chinese Ministry of National Defense said majority of the Chinese government websites including the Department of Defense were targeted by hackers about 144,000 times in a month and two-thirds originated from the United States, Reuters has reported citing the China’s official Xinhua News Agency.