It's believed the Haiwangxing wants to monitor upcoming military exercises involving Australia and the US. (Department of Defence)
Beijing has dispatched a second high-tech surveillance ship to Queensland as large-scale military exercises involving Australian and American forces ramp up.
Just days after the ABC revealed a People's Liberation Army-Navy (PLAN) vessel was being tracked by the ADF, defence sources have confirmed another intelligence-gathering ship is soon expected to also arrive off the east coast.
One military official, who spoke to the ABC on the condition of anonymity because they were not authorised to comment publicly, said the Haiwangxing (which translates as "Neptune") had been "on our radar for some time".
The Haiwangxing is an auxiliary general intelligence (AGI) vessel and a younger sister ship to the Tianwangxing ("Uranus"), which is already believed to be closely monitoring this year's Exercise Talisman Sabre.
For the past two Talisman Sabre exercises in 2019 and 2017, China has deployed an AGI to study how US forces interact with their Australian allies, but this is the first occasion a second surveillance vessel has come.
Australia, like the United States, also regularly deploys intelligence-gathering assets to monitor the military activity of other nations, but defence officials believe it is "unusual" two Chinese ships are monitoring Talisman Sabre in 2021.
The Tianwangxing was tracked by the ADF as it transited through the Torres Strait towards Queensland waters, but the Haiwangxing is approaching through the Solomon Sea around Papua New Guinea.
So far, the Defence Department has not commented publicly on the impending arrival of the second Chinese surveillance ship, despite being approached by the ABC on Friday.
A spokesperson for Defence Minister Peter Dutton has also, so far, not responded to questions from the ABC.
In the past week, the US has fired a Patriot missile for the first time on Australian soil as part of the 'Talisman Sabre' training activity, which takes place every two years.
On Sunday, the US military is expected to do a live-fire demonstration of its High Mobility Artillery Rocket System (HIMARS), technology which the ADF could soon purchase.
Talisman Sabre is described as "Australia's largest war-fighting exercise", but this year the number of international participants has been scaled back due to COVID-19.
Along with forces from the US and Japan, this year the activity will also include military personnel from Canada, South Korea, New Zealand and the United Kingdom.
Both Chinese Type 815 ships are expected to remain outside Australian territorial waters but within Australia's exclusive economic zone (EEZ) as they monitor the fortnight-long war games.
ANU Law Professor Donald Rothwell said if both PLAN vessels remained outside Australia's "12 nautical miles" limit while operating in the EEZ, their activity would be consistent with freedom of navigation laws under the UN Convention on the Law of the Sea.
"The Torres Strait is an international strait under the 1982 UN Convention on the Law of the Sea and that status is universally recognised," Professor Rothwell said.
"It is questionable whether any intelligence-gathering activities by the Tianwangxing while passing through the Torres Strait are permissible under the Convention."