Australia should consider tightening a provision allowing the US and the UK to walk away from the AUKUS nuclear submarines deal with a year's notice, an international law expert has advised a parliamentary committee.
ANU international law professor Donald Rothwell said enormously flexible withdrawal terms laid out in a new AUKUS treaty, tabled in parliament earlier this year, could have "significant implications" for Australia's national security prospects and future ability to procure nuclear technology.
Defence Minister Richard Marles signed off on the revamped deal with US and UK counterparts in May, which agreed to a legal framework for the transfer of nuclear materials and equipment for Australia's $368 billion acquisition of nuclear submarines.
Political agreement documents later tabled in August revealed it will "remain in force until December 31, 2075" but added any party may terminate it "by giving at least one year's written notice" to the other countries.
"This agreement in my experience is somewhat exceptional [...] because it allows for an enormous amount of flexibility on the part of Australia's principal partners in this trilateral agreement to withdraw on multiple different circumstances," Dr Rothwell told a hearing on Wednesday.
"Under many treaties, there are much more limited and constraints in which another party might seek to withdraw.
"A recommendation could be, that some of those provisions I've generally alluded to, could be tightened up - or they could even be removed. Whether or not that would meet the agreement would remain to be seen."
Under the new AUKUS deal, Australia has agreed to take responsibility for nuclear safety risks and will indemnify the US and the UK "against any liability, loss, costs, damage or injury" that arise during the transfer and building process.
Critics of the $368 billion AUKUS plan have raised questions over whether the US will allow Australia to control the second hand US-built boats, the first of which is expected to be sold and delivered by 2032.
From a legal perspective, Dr Rothwell told the committee there were no specified terms in the treaty or in agreement documents to suggest Australia would have full ownership.
"Once these submarines are launched, there's nothing to suggest in this instrument [..] that it would only be Australia that would control the way in which these submarines are operated," he said.
He also noted that a series of additional side agreements and instruments will evolve with the agreement until its expiry in 2075.
"One important recommendation that the committee could make was to ensure there was a parliamentary scrutiny of any supplementary or additional side instruments that this 2024 agreement spurns," Dr Rothwall said.