Suguru Maehara, a 38-year-old sergeant of the Ground Self-Defense Forces, was involved in the accident on Tuesday last week, according to a GSDF spokesman who confirmed his death.

"It is the first time a GSDF member has died during an overseas drill," the spokesman told AFP.

Maehara was delivering food supplies to members participating in the drill when the accident happened.

The exercise, codenamed Kamandag (meaning 'Venom'), marked the first time Japanese armoured military vehicles were used on foreign soil since the country adopted a pacifist constitution after its 1945 defeat.

But Japan is not involved in the combat component of the military exercises.

The 10-day exercise is being held at a Philippine navy base facing the South China Sea, some 250 kilometres (155 miles) from the Scarborough Shoal -- a territory claimed by Manila that was seized by China during a 2012 naval stand-off.

Local media reported that Maehara was in a vehicle driven by a Philippine man near the naval base.

Another Japanese officer in his 40s who was in the same vehicle was injured with a broken rib. He was sent to a hospital with Maehara but was discharged on the same day, the GSDF spokesman said.

A Philippine spokesman for the exercises declined to comment.

The Philippines has ramped up military cooperation in recent years with Washington, its long-time ally, and also held joint naval exercises with Japan near Scarborough Shoal in 2015.

Japan has its own maritime territorial dispute with Beijing in the East China Sea, where China has built artificial islands and installed military facilities on them.

The US military stressed that Saturday's exercise was not aimed at China.