The missiles were installed in Kumamoto in the southern region of Kyushu, as Japan is attempting to shore up its military capacity as China steps up naval activity in the East China Sea.

"Standoff defense capabilities enable us to counter the threat of enemy forces attempting to invade our country... while ensuring the safety of our personnel," said Defence Minister Shinjiro Koizumi.

"This is an extremely important initiative for strengthening Japan's deterrence and response capabilities," he added.

The surface-to-ship guided missile system has a range of around 1,000 kilometres (620 miles), putting parts of the Chinese mainland within reach -- Shanghai lies about 900 kilometres from Kumamoto.

Koizumi also said a "hyper velocity gliding projectile", designed to defend remote islands from enemy forces, had been deployed in Shizuoka, another coastal area closer to Tokyo which faces the Pacific.

Japan has long had a policy to use its military only for self defence in its most strict meaning.

But in recent years Tokyo has steadily built its defence capacity as regional neighbours including China, Russia and North Korea increase their military activities in the region.

In 2022 it approved a plan to deploy missiles with counter attack capability.

"If we continue to rely solely on ballistic missile defence... it will become increasingly difficult to fully address the threat" of missiles with advanced technologies, a defence white paper issued last year said.

China is beefing up its military and is engaged in a number of territorial disputes with other countries in the region, including Japan over the Senkaku Islands, known as the Diaoyu in China.

Japan's ties with Beijing have soured in recent months after Prime Minister Sanae Takaichi hinted in November that Tokyo could intervene militarily in any attack on self-ruled Taiwan.

China views Taiwan as its territory and has not ruled out taking it by force.

Critics of Tokyo's move to deploy missiles could make the area a target of possible enemy attacks.

Earlier this month, local media reported that Japan's ground force delivered a launcher for the missiles to Kumamoto without warning local communities, prompting dozens of opponents to stage a protest in front of a local military base.