The federal government has refused to release advice given to the prime minister's office about possible "paths forward" for the Darwin Port on the grounds it could "cause damage to the defence of the Commonwealth".
Following Labor's election victory last year, Anthony Albanese announced a fresh review into the circumstances surrounding the 99-year lease of the port to Chinese company Landbridge in 2015.
The review's terms of reference are yet to be disclosed, but a Freedom of Information (FOI) request by the ABC last month revealed the Department of Prime Minister and Cabinet had asked national security agencies for any assessments of the port conducted in 2022.
The released documents also included a timeline which showed the department had provided advice to the prime minister's office about "paths forward for consideration of the Port of Darwin lease" in September last year.
The ABC sought access to that advice, but the department has now rejected the request, saying the information is exempt under the FOI Act.
In its decision, the department said:
"The document falling within the scope of your request includes material that, if released, would disclose existing arrangements for the security of Commonwealth interests.
"[The department has] formed the view that release of the documents is likely to compromise the safety, protection and defence of those interests, and [it is] satisfied that the documents are exempt in full."
The timeline also showed that the department provided advice to Mr Albanese's office in August last year about a separate Defence review of the port commissioned by the former Morrison government in 2021.
The ABC applied for access to that advice, but it was also refused on the same grounds.
"The document … includes material that, if released, would reveal [or] compromise defence arrangements and capabilities," the department stated.
The Defence review has never been publicly released, but media reports in December 2021 said it had found no sufficient grounds to overturn Landbridge's lease.
Details of review remain 'classified'
Assistant defence minister Matt Thistlethwaite said the government's multi-agency review of the port was ongoing.
"Some of that information is classified so it's not appropriate for me to discuss it publicly," he said.
"But once that review is conducted, the findings will be handed down, and we'll get on with the job of ensuring we are securing Australia's assets in the north."
Landbridge, which is owned by Shandong-based billionaire Ye Cheng, secured the long-term lease of the port as part of a $506 million deal with the former territory government.
The NT retains ownership of the port and a 20 per cent stake in the lease.
But despite receiving approval from national security agencies at the time, the lease became the subject of controversy as the relationship between the Australian and Chinese governments deteriorated in the years following the signing of the deal.
Landbridge declined to comment on the government's decision to block access to the advice given to Mr Albanese's office last year.
However, the company has previously rejected claims that the Chinese government has any influence over its operations at the Darwin Port, which are managed by an Australian workforce.
"Landbridge would expect the federal government to undertake a comprehensive review using all its agencies to address any concerns it may have," the company said last month.
"The agreement with the NTG has been reviewed a number of times previously and Landbridge's position remains that the lease is a commercial arrangement with the NTG and believes that there are no grounds on which the lease could be disputed."