Labor senator Kimberly Kitching used parliamentary privilege to ask the head of Australia's counter espionage agency whether Dr Chau was the man referred to in his annual threat assessment speech.

The case involved an unnamed wealthy person - described as the "puppeteer" - who had "direct and deep connections with a foreign government and its intelligence agencies", ASIO Director-General Mike Burgess said.

It was later revealed by Nine newspapers that this person was an unnamed Chinese businessman who had tried to bankroll potential federal NSW Labor candidates and get sympathetic MPs elected to parliament.

"I am reliably informed that the puppeteer mentioned in your case study in your annual threat assessment speech given last week is Chau Chak Wing," Senator Kitching said during a Senate estimates hearing.

But Mr Burgess wouldn't be drawn on the man's identity, telling the hearing it was "unfair" of the senator to publicly ask him such a question.

"I will not comment on speculation of who is and who isn't targets, in general, or in specific," he said.

Dr Chau has since called for Senator Kitching to "show some courage and integrity" by repeating her claim outside of privilege and revealing the sources she says she relied on.

"It is always unfortunate when elected representatives use the shield of parliamentary privilege as a platform to vilify and attack Australian citizens without producing a shred of evidence," he said.

"I am a businessman and philanthropist. I have never had any involvement or interest in interfering with the democratic election process in Australia."

Dr Chau referred to his defamation case with the ABC, Nine and Nick McKenzie, an investigative reporter at The Age and The Sydney Morning Herald, over the joint report "Power and Influence".

"In 2017, the ABC and Nine journalist Nick Mckenzie made a similar allegation in a Four Corners report. The Federal Court subsequently awarded me very substantial damages which I donated to charity," he said.

The billionaire was awarded $590,000 in damages in 2021 after a Federal Court judge found he had been defamed.

While Justice Steven Rares rejected a claim the report aired on Four Corners and published in Nine outlets imputed Dr Chau was a spy for China, he did find the report suggested he paid huge bribes to Australian political bodies to advance China's interests.

Labor's home affairs spokeswoman says she wouldn't have outed the identity of a suspected foreign influencer.

Senator Kristina Keneally said "individual senators can make individual decisions about the questions they ask", but "weaponising" national security harms the community.

"A range of senators from a range of political parties have questions that I would not ask in a public forum," she said.

"I would encourage all members of parliament to take heed of the ASIO director-general's advice about the importance of keeping national security information and intelligence information confidential."

Senator Keneally said she hasn't had the opportunity to raise her concerns directly with her colleague.

Opposition Leader Anthony Albanese has defended his party, saying last week that Mr Burgess had never raised concerns with him about any Labor candidates.

When asked whether there were concerns about foreign interference involving any of Labor's federal candidates, Mr Burgess said Mr Albanese "gave an accurate account of the conversation I had with him last week when he asked me that question".

Senator Keneally said the ASIO director-general had made clear people shouldn't assume the report in the Nine newspapers is accurate or true.

"(Mr Burgess) pointed out some of the inconsistencies if you compare what was reported in the Nine newspapers to what was in his annual threat assessment," she said.

Australian Associated Press