A wave of cyberattacks has struck multiple Australian pension funds, compromising thousands of member accounts in the nation's massive A$4.2 trillion ($2.66 trillion USD) retirement savings sector, the country’s top cyber official confirmed on Friday.

Michelle McGuinness, Australia’s National Cyber Security Coordinator, said in a public statement that authorities are actively responding to a coordinated effort by cybercriminals targeting superannuation account holders. She noted that the government is working closely with affected institutions to contain the threat.

AustralianSuper, the nation’s largest pension fund with A$365 billion under management and more than 3.5 million members, revealed that hackers had stolen up to 600 member passwords in an attempt to commit fraud.

"We acted quickly to lock down the affected accounts and notified the impacted members," said Rose Kerlin, the fund’s chief member officer.

REST Super, which manages A$93 billion and serves mainly retail employees, also fell victim to the breach. CEO Vicki Doyle reported that about 1% of its 2 million members were affected by a cyberattack last weekend.

Insignia Financial, the largest operator of retail superannuation platforms in Australia with A$327 billion in assets, disclosed that an attempted intrusion had occurred on its Expand platform. While the source was described as a “malicious third party,” Insignia stated there had been no financial losses reported so far.

Several other pension funds have yet to issue public responses regarding their exposure to the incident.