Australia’s top-ranked university says it has spent several months fighting off a threat to its computer systems, which some media reports say have been compromised by Chinese hackers.

Repeated allegations of hacking and internet spying have contributed to a recent chill in Sino-Australian relations, just as they have long strained ties between China and the United States.

Networks at the Australian National University in Canberra, which is home to several defence-focused research units, were breached “months ago” by attackers whom authorities traced to China, said Channel Nine television and Fairfax Media websites, citing “multiple” unnamed security and intelligence sources.

In a statement, ANU said it believed no staff, student or research information was stolen as a result of the latest “threat”, which it has been working to contain “for several months”.

The government said “nation states and criminal groups” were known to target universities to steal intellectual property, without naming China or identifying the source of the attack.

It was “working closely” with the university on the matter, a spokeswoman said in an email.

China has consistently and strongly denied being involved in any hacking attacks and its embassy in Australia, as well as the foreign ministry in Beijing, did not immediately respond to a request for comment.

The news comes as tension flares over new Australian laws that seek to curb foreign interference, measures the prime minister, Malcolm Turnbull, has said were adopted to allay concerns over Chinese influence in politics and universities.

Australia’s cyber security agency has also previously blamed a foreign intelligence service, without identifying it, for a 2015 malware attack on the weather bureau.

“We don’t have information on this specific incident [but] organisations which conduct research with defence applications are regularly targets of advanced cyber attacks,” said Tim Wellsmore of cybersecurity firm FireEye Inc.

“We have observed Chinese state-sponsored attackers target research institutions in Australia in recent years, and we have observed other state-sponsored groups targeting these institutions in Asia,” added Wellsmore, the firm’s director of government security programs in the Asia-Pacific region.

In recent years, the media have attributed the weather bureau attack and the theft of spy-office blueprints to China-backed hackers.

In 2017, the Australian government admitted that a hacker stole 30 gigabytes of non-classified data about the Joint Strike Fighter program, as well as other military hardware.