THE Collins-class submarine HMAS Waller. Australia plans to replace the Collins class submarine with a new fleet of nuclear attack submarines with assistance from the UK and US.

THE PHILIPPINES is backing a defense pact that allows Australia to build nuclear-powered submarines using technology that the United States had only previously shared with Britain, saying it could keep the balance of power in the Indo-Pacific region.

“The fresh enhancement of Australia’s military capacity through this trilateral security partnership would be beneficial in the long term,” Philippine Foreign Affairs Secretary Teodoro L. Locsin, Jr. said in a statement posted on the agency’s website on Sept. 19.

His view differs from that of neighboring Indonesia and Malaysia, which warned that the alliance could provoke a nuclear arms race in the region. Singapore was more neutral, saying it hoped the deal “would contribute constructively to the peace and stability of the region and complement the regional architecture.”

China, the unspoken target of Washington’s latest effort to boost its influence in the region, criticized the agreement.

Chinese Foreign Ministry spokesman Zhao Lijian last week said the pact “seriously undermined regional peace and stability, exacerbated the arms race and undermined international nuclear nonproliferation efforts.”

Mr. Zhao added that any regional alliance “should not target or harm the interests of third parties.”

“Australia’s actions reflect its concerns about this geographic imbalance and its desire to help maintain regional peace and security,” Mr. Locsin said. “That is its prerogative.”

He added that without an actual presence of nuclear weapons, the military alliance does not violate a 1995 treaty to keep nuclear arms out of Southeast Asia.

He said the Philippines was open to discussing this with other governments. “We appreciate Australia’s continued and absolute commitment to meeting its obligations under the Nonproliferation Treaty and to the highest standards of nuclear stewardship.”

The pact also allows for greater collaboration among the three countries on cyber-capabilities and artificial intelligence.

It will make Australia the seventh country in the world to have nuclear-powered submarines, after the US, Britain, France, China, India and Russia.

The South China Sea remains a source of tension as the US, one of the Philippines’ oldest allies, and other Western countries hold so-called freedom of navigation operations to keep China, which claims more than 80% of the sea, at bay.

President Rodrigo R. Duterte, who has sought closer and investment ties with China since he became President in 2016, has said the Philippines could not afford war with China, adding that the sea dispute should be resolved peacefully.

Members of the Association of Southeast Asian Nations (ASEAN) “singly and collectively do not possess the military wherewithal to maintain peace and security in Southeast Asia, discourage the sudden creation of crises therein, and avoid disproportionate and hasty responses by rival great powers,” Mr. Locsin said.

“Preventive diplomacy and the rule of law do not stand alone in the maintenance of peace and security,” he added.

He also cited an imbalance in the forces available to ASEAN member states, “with the main balancer more than half a world away.”

Mr. Locsin said Australia’s ability to project power should restore and keep the balance rather than destabilize it.

He also noted that despite advances in military science, time, distance and water remain major constants in determining security capacity to respond to threats.

“The Philippines aspires for the South China Sea to remain a sea of peace, security, stability, and prosperity,” the country’s top envoy said. “We are acutely aware of great power dynamics; with a sharp eye we will engage in practical and mutually beneficial cooperation aligned with the priority areas of the outlook.”

The trilateral military alliance had also incensed France, which felt its Indo-Pacific interests had been torpedoed by the submarine deal. The pact brought its own 2016 deal to build submarines for Australia to an abrupt end.

Australian Prime Minister Scott Morrison has said that in spite of the hard feelings among rivals and allies, the deal with the US and Britain was an opportunity his country could not turn down.

The advantages of nuclear submarines were clear, he said. “They’re faster, they have greater power, greater stealth, more carrying capacity.” — Norman P. Aquino