Brisbane, Mar. 29 : A Chinese-Australian woman, who is at the centre of a top-level espionage inquiry met both Prime Minister Kevin Rudd and former PM John Howard at a private dinner here in 2004.

Rudd is believed to have talked at length in Mandarin with Helen Liu, who is at the centre of allegations that the nation''s top spy organisation, the highly-secretive Defence Signals Directorate (DSD), tapped into the laptop of Defence Minister Joel Fitzgibbon, without his knowledge.

The DSD allegedly discovered Liu''s bank account details in Mr Fitzgibbon''s computer.

The minister, who denies any wrongdoing, rents a Canberra flat from Ms Liu, a family friend for more than 16 years.

The Inspector General of Intelligence and Security, Ian Carnell, has now launched a formal investigation into claims that DSD spied on the minister and all "related matters".

It''s now alleged that Rudd attended the 2004 dinner with Liu, at the invitation of another major ALP donor and known Labor supporter, Brisbane property developer Maha Sinnathamby, whose personal fortune is estimated at 571 million dollars.

Sinnathamby's spokesman confirmed yesterday that he had known Rudd for more than 20 years and had dined privately with him on a number of occasions, as well as at numerous larger public functions, but could "not recall" the 2004 dinner allegedly attended by both Liu and Rudd.

Rudd's spokesman refused to deny the claims that he had dined with Liu in 2004, saying only: "The Prime Minister attends hundreds of functions and meets thousands of people every year."

The undated photograph of Howard with Liu appears to have been taken at a public function.

Howard is known to have enduring and good relations with the Sydney Chinese business community. He had a large number of Chinese residents in his former seat of Bennelong. (ANI)