Australia's top-ranked university said on Tuesday hackers breached its cyber defences late last year to obtain sensitive data of students, including bank account numbers and passport details, going back nearly two decades.
The Australian National University (ANU) said the breach was carried out by "a sophisticated operator", without elaborating.
An earlier cyber-attack, disclosed by ANU in July last year, had failed to gather sensitive information. Media reports at that time had cited sources saying that the hacking originated in China.
According to World University Rankings, ANU is Australia's best university and many of its graduates go onto to hold senior government positions, magnifying security sensitivities over the data breach.
"National community agencies are recruiting directly out of ANU," said Fergus Hanson, head of the International Cyber Policy Centre at think-tank the Australian Strategic Policy Institute.
"To have information around particular people who are working in different departments...that would be very useful."
China has consistently denied being involved in any hacking attacks and its embassy in Australia, as well as the foreign ministry in Beijing, did not respond to a request from Reuters for comment.
Despite Chinese denials, Australia has cited similar incidents as evidence that China is meddling in its domestic affairs.
The allegations strained ties between China and Australia, a strong US ally.
© Thomson Reuters 2019