The Reverse Bank said that a third party file sharing service used by the Bank to share and store some sensitive information was targeted in the hack.

Governor Adrian Orr said the breach was contained and that the Reserve Bank was treating the matter with the highest priority and urgency.

"We are working closely with domestic and international cyber security experts and other relevant authorities as part of our investigation and response to this malicious attack. The nature and extent of information that has been potentially accessed is still being determined, but it may include some commercially and personally sensitive information," Orr said in a statement shared by the bank.

The file sharing system was taken offline while initial investigations are underway, Orr added, saying "it will take time to understand the full implications of this breach."

According to the Sydney Morning Herald, the central bank holds data on operations of all banks in the country and is tasked with advising them on cyber security matters.