The two countries' shared grievances over Chinese territorial claims have seen them draw increasingly close in recent years, including the signing of a reciprocal access agreement allowing for the deployment of troops on each other's territory.

Defence Minister Shinjiro Koizumi's visit came as a contingent of 1,400 Japanese personnel was participating for the first time in annual US-Philippine military exercises, and just weeks after Tokyo eased decades-old arms export rules in a major policy shift.

Speaking alongside Philippine counterpart Gilberto Teodoro, Koizumi -- who signed a defence pact with Indonesia a day earlier -- said that the two countries would create a working group focused on defence equipment.

"We agreed to move forward with discussions aimed at realising comprehensive equipment cooperation... with a view to the early transfer of Abukuma-class destroyers and TC-90 aircraft as well as other defence equipment," Koizumi said.

The Abukuma-class vessels, which are being retired by Japan, have been on the Philippines' radar for some time, with the military saying it would send a contingent to examine them in 2025.

Speaking to reporters after the briefing, Teodoro said the destroyers would be a donation rather than a purchase, without specifying how many would be involved.

"The transfer is a giveaway," he said, adding the Philippines would also now "be able to buy defence equipment" given the recent shift in Japanese policy.

Japanese media have reported that offering the destroyers free of charge or at a steeply discounted rate would require further changes to the country's self-defense laws.

Koizumi reiterated Japan's opposition to the use of "force or coercion in the East China Sea and the South China Sea", noting what he called an "increasingly tense regional environment".

China has deployed navy and coast guard vessels in a bid to bar the Philippines from strategically important reefs and islands in the South China Sea, leading to a string of confrontations.

Beijing claims the crucial waterway in nearly its entirety despite an international ruling that its assertion has no legal basis.

Tokyo, meanwhile, has been a key financer of Philippine efforts to modernise its South China Sea patrol craft as well as maritime surveillance systems.

Earlier this year, the two countries signed a fuel and ammunition resupply agreement.

Both Koizumi and Teodoro are expected to travel to Ilocos Norte province to watch on Wednesday as Japan uses a Type 88 anti-ship missile to sink a decommissioned World War II-era navy ship.

US, Philippine and Canadian forces will also take part in the exercise.