A total of 17,680 soldiers will take part in the annual drills, which for the first time will include live-fire exercises in the disputed South China Sea and a simulated defence of a tiny Philippine island nearly 300 kilometres (190 miles) south of Taiwan.

The countries will also stage an amphibious landing on the western island of Palawan, the closest Philippine landmass to the Spratly Islands -- a flashpoint for Beijing and Manila.

"Any armed forces has the right to conduct military exercises," said Colonel Michael Logico, the Philippine spokesman for the war games called Balikatan, which means "shoulder to shoulder" in Filipino.

"It's really part of our combat readiness," he said.

The announcement comes less than six weeks after Manila and Washington agreed to restart joint patrols in the South China Sea, and struck a deal to give US troops access to another four military bases in the Southeast Asian country.

The countries have been seeking to repair ties that were fractured under President Ferdinand Marcos's predecessor Rodrigo Duterte.

Beijing's growing assertiveness on Taiwan and its building of bases in the South China Sea have given fresh impetus to Washington and Manila to strengthen their partnership, which is underpinned by a mutual defence treaty.

The exercises, scheduled for April 11-28, will involve more than 12,000 American, nearly 5,000 Filipino and 111 Australian soldiers -- about twice as many as last year, Logico said.

A US official confirmed the figures.

One of the drills will involve military helicopters landing on Calayan island, off the northern tip of the main island of Luzon.

The maritime and coastal defence drill has been held in the past, but this will be the first time on Calayan.

It will also be the first time Philippine and US navy frigates will fire their weapons towards the South China Sea from waters off Zambales province, north of Manila, Logico said.

Previous live-fire exercises were held on land.

The Americans will also use their Patriot missiles, considered one of the best air defence systems in the world, and the HIMARS precision rocket system during the drills.

The Australian troops involved will mainly take part in "special operations" type exercises, Logico said, while Japan will send an observer delegation.

This is the first Balikatan to be held since Marcos took power in June 2022.

Marcos has insisted he will not let China trample on the Philippines' maritime rights -- in contrast to Duterte who was reluctant to criticise Beijing.

Beijing claims sovereignty over almost the entire South China Sea, including the Spratlys, ignoring an international ruling that its claims have no legal basis.

The Philippines and several other countries have rival claims.

The US and Australian embassies in Manila did not immediately comment on the exercises.