He also launched an incendiary attack on the government's policy. "I understand my responsibilities as a former cabinet minister," Mr Robb said. "The register is a political stunt, you would expect people like myself to have a clear understanding about the ethics of what I'm doing." He added that "attempts to trash my reputation in some quarters – now being aided and abetted by the government – are ill-informed and cheap politics". The United States under Donald Trump, not China, was the "biggest source of instability" in the region, he said, adding its withdrawal from the Trans-Pacific Partnership had effectively handed China "endless opportunities in a trade and investment sense". Mr Robb helped negotiate the TPP as trade minister. Attorney-General George Brandis suggested on Tuesday that Mr Robb would have to sign up to the new register.

However, the requirement to register his deal with Landbridge was likely to be more complicated given the firm seeks to play down its close ties to the Chinese Communist Party, and the nature of Mr Robb's deal is cloaked in confidentially. Though the $880,000 yearly payment from Landbridge to Mr Robb – beginning shortly after he left parliament in 2016 – was revealed by Fairfax Media and Four Corners in June, the full details in the letter to Mr Robb were only recently leaked by a source with concerns about the nature of the deal. One government official described it as a "disgraceful" look for a former cabinet minister. Billionaire Ye Cheng is the owner of Landbridge, which controversially acquired the 99-year lease for the Port of Darwin in 2015. He is also a member of the national Chinese People's Consultative Committee, an advisory body that President Xi Jinping has directed to "uphold the CPC [Chinese Communist Party] leadership without wavering". Headed "Consultancy Agreement" and addressed to "Dear Andrew" the entire deal is detailed on a single page containing seven terms.

"The appointment of AR [Andrew Robb] will be confidential except as agreed in writing," the letter states. "Westside [a subsidiary of Landbridge] will engage AR as a consultant from 1 July 2016 and is subject to annual review with any resulting agreed amendments to be recorded in writing and to apply from date as is then agreed. This agreement may be terminated by either party (without cause) on thirty days' written notice being provided to the other party." "In acting as a consultant, AR will (through Andrew Robb Pty Ltd) provide consulting, strategic and other services as agreed with LI [Landbridge]. The authorised persons for LI are Cheng Ye and (CEO) Mike Hughes. During the consultancy, AR will be remunerated $800,000 per annum plus applicable [tax] and payable in equal monthly instalments." Mr Ye frames much of his business activity, including the acquisition of the Port of Darwin lease, in terms of advancing Beijing's ambitious global trade and infrastructure policy "One Belt, One Road". Mr Robb has also advocated for Australia to back the policy.

Former NSW judge Mr Whealy, who now chairs integrity NGO Transparency International, examined the key terms in the leaked letter for Fairfax Media. "What I take from the letter is that the position of Andrew Robb does raise serious questions for a person formerly of high government position going into business with a company close to a foreign power." "It is just extraordinary that aren't more questions haven't been asked about this deal. The terms really oblige Mr Robb to do nothing and he gets nearly a million dollars a year for it." But Mr Robb said his contract was "a typical commercial contract", and that "I'm not doing business in Australia, so what is the relevance of my contract with the company?" "The contract is with a foreign company to do work in other foreign countries. The document doesn't say I was lobbying for Landbridge," he said.

In a statement, Landbridge stated Mr Robb was not engaged in political representation for the company in Australia. "Landbridge is a private commercial Chinese company. It made no secret of Mr Robb's appointment which was publicly announced in China. Mr Robb works for Landbridge outside Australia, predominantly in China and South East Asia assisting Landbridge develop trade through Darwin Port." Another expert, Howard Whitton, said it was concerning the letter did not explicitly prohibit Mr Robb from relying on knowledge gained during his time overseeing Australia's trade relations and policy. "The Prime Minister's Statement of Ministerial Standards require Ministers to undertake that, on leaving office, they will not take personal advantage of information to which they have had access as a Minister, where that information is not generally available to the public. This obligation is not time-limited," Mr Whitton said. "Given the apparently open-ended agreement under which Mr Robb was to provide advice on business matters, and his former position as a senior cabinet minister responsible for trade and investment, it is difficult to know how he is able to comply with that undertaking."