Prime Minister Malcolm Turnbull has defended a Liberal MP who used parliamentary privilege to allege a Chinese-Australian billionaire was involved in bribing the late UN president.
Andrew Hastie used parliamentary privilege to announce a man known as "CC-3" in FBI documents about the bribery case is political donor Dr Chau Chak Wing.
"The same man who co-conspired to bribe the United Nations general assembly president John Ashe, the same man with extensive contacts in the Chinese Communist Party," Mr Hastie said in parliament on Tuesday night.
Mr Turnbull says it was Mr Hastie's right to make speeches in parliament without fear of being sued for defamation.
"The allegations are not new, they've been made elsewhere and they are the subject of legal proceedings," Mr Turnbull told reporters on Wednesday.
"I'm not going to comment on a member of parliament using their right ... it's a right that was hard won, it's a fundamental part of our parliamentary democracy.
"The first I learned of Mr Hastie's remarks was after he had given them ... I had no forewarning of it."
Mr Hastie tabled US State Department cables about Dr Chau's links to the Communist Party.
The FBI claimed Chinese-Australian woman Sheri Yan used $US200,000 of CC-3's money to bribe Mr Ashe in November 2013.
She's pleaded guilty to the bribery charge and is serving a 20-month sentence.
Mr Hastie told parliament Dr Chau had undertaken defamation proceedings against the ABC and Fairfax.
News Corp also had to apologise to him.
Mr Hastie maintained it was in the national interest to name Dr Chau, in part because defamation cases had a "chilling effect" on a free press.
Mr Hastie, who chairs the joint parliamentary committee on intelligence and security, led a delegation to the US last month and was able to confirm the man's identity.
Dr Chau has not been charged in the US, he said.
Green MP Adam Bandt said the speech showed the need for a federal corruption watchdog.
"If we had a corruption watchdog they could investigate these claims and get to the bottom of it," he told reporters.
"A federal corruption watchdog would be able to do more than raise claims under parliamentary privilege."