Australians have been urged to be vigilant with their personal information after fraudsters attempted to access the superannuation accounts of up to 150 Australians.
Five search warrants have been executed in relation to the fraud, Australian Federal Police commissioner Reece Kershaw told a Senate inquiry on Thursday.
Australians are able to access their super early to help them financially during the coronavirus pandemic.
Bank accounts containing about $120,000 have been frozen.
No government systems have been hacked, Mr Kershaw said, but a third party provider has been.
The fraud relates to more than one superannuation provider and the attack may relate to a tax agent.
"It is quite sophisticated," Mr Kershaw said.
Labor's financial services spokesman Stephen Jones says better protections need to be put into place, by bringing together all security agencies.

A line at a Centrelink office in March. Source: AAP
"We'd like to see frauds prevented before they occur," he told reporters in Canberra.
Australian Taxation Office boss Chris Jordan has urged the public to remain vigilant with their information.
"I would really wish to emphasise that people do keep personal information secure and private," he told the inquiry.
The fraud was first detected by Austrac and the ATO was alerted on 30 April, before it was referred to the police a day later.
Industry Super Australia raised concerns with the government about the potential for fraudulent claims, and was told the ATO had checks to guard against fraud.
More than one million applications for early super have been approved, totalling about $9 billion.
Labor leader Anthony Albanese says Australians should never have been able to access their retirement savings early.
"We should be ensuring that superannuation is for people's retirement," he said.
"The government has to explain why it is that the mechanisms weren't in place to protect people's savings."
The Senate inquiry is looking into the government's response to the coronavirus pandemic.
People in Australia must stay at least 1.5 metres away from others. Check your state’s restrictions on gathering limits.
Testing for coronavirus is now widely available across Australia. If you are experiencing cold or flu symptoms, arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
The federal government's coronavirus tracing app COVIDSafe is available for download from your phone's app store.
SBS is committed to informing Australia’s diverse communities about the latest COVID-19 developments. News and information is available in 63 languages at .