Australia will equip its warships with some of the world’s most advanced air- and missile-defense systems after signing an agreement worth 7 billion Australian dollars ($4.7 billion) with the United States to acquire SM-2 IIIC and SM-6 missiles, similar to those being procured by Japan.

These long-range weapons will be progressively rolled out across the Royal Australian Navy’s three Hobart-class destroyers, each of which can carry 48 of such missiles, and six future Hunter-class frigates, which hold 32 missiles.

The purchase comes as Australia prepares to combat threats faster and further away, and alongside regional partners concerned over China’s rapid military build-up.

These missiles “will enable our Navy to strike maritime, land and air targets at long range, and provide a terminal ballistic missile defense capability,” Australian Defense Minister Richard Marles said in a statement Tuesday.

The announcement follows the successful test-firing of an SM-6 from the HMAS Sydney Hobart-class destroyer in August, a move that Defense Industry Minister Pat Conroy said made Australia the first country other than the United States to fire the weapon.

The SM-6 is seen as the most advanced air-defense missile in the U.S. Navy’s arsenal.

No information was provided, however, on how many missiles Canberra is purchasing from Washington or when they will be delivered.

“This investment in naval interceptors won't be the end of the story, but it's a good step toward filling in that force structure gap,” said Tom Corben, a defense and foreign policy expert at the United States Studies Center in Sydney.

“These sorts of capabilities will be critical for rounding out Australia's ability to execute a strategy of deterrence by denial,” he added.

The announcement comes after Australia outlined in April last year a more assertive defense posture that prioritizes new technologies as well as maritime and long-range strike capabilities.

In a declassified version of the country’s Defence Strategic Review, Canberra concluded that it must “re-posture,” since it was no longer protected by its geography and the limited ability of other nations to project power as the world entered a "missile age."

"We live in the greatest arms race in our region since 1945, with a high degree of strategic uncertainty," Conroy was quoted by Australia’s public broadcaster as saying.

"You just have to look at the lessons from the Ukraine conflict to understand the importance of air defense and the ability to defend against missile threats," he added.

Malcolm Davis, a security expert at the Australian Strategic Policy Institute, said the latest move had been anticipated for several years, following the previous government’s release of its 2020 Defence Strategic Update and Force Structure Plan.

Davis also said it was unambiguous who the move is intended to deter.

“This is clearly a reaction to growing missile capabilities of China’s People's Liberation Army, Navy, Air Force and Rocket Force, all of which continue to increase the threat level posed to Australia and its allies,” he said.

The move also comes after the Japanese and U.S. leaders unveiled a vision in April to cooperate with Australia on a networked air-defense architecture aimed at countering “growing air and missile threats.”

While Canberra’s latest announcement isn’t necessarily related to those discussions, Davis said ensuring that the three partners are using the same missile tech would open up the opportunity for establishing an integrated air- and missile-defense architecture.

The Maritime Self-Defense Force is currently procuring the SM-6 for its two Maya-class guided-missile destroyers and could also field the missiles in the two dedicated air-defense vessels it plans to commission in March 2028 and March 2029, respectively.

While the MSDF fields the earlier SM-2 IIIB version, Davis said it would make “eminent sense” for Tokyo to upgrade to the latest model to ensure commonality with the U.S. and Australian navies.

Corben said that acquiring the same capabilities would “grease the wheels” for an integrated air- and missile-defense architecture that is also “interchangeable rather than just interoperable.”

Going forward, it will be important for all three countries to build on these developments by exploring the potential for Australia and Japan to manufacture the interceptors domestically, he said.

This, he added, would allow them to meet independent and trilateral requirements while certifying members of their militaries to load, maintain and generally operate these systems aboard one another's ships.