Speaking ahead of a visit to Beijing, Japanese Foreign Minister Fumio Kishida on Monday said China's activities had "not only people in Japan, but countries in the Asia-Pacific region and the international community greatly worried."

Relations between the two countries have long been strained over competing territorial claims in the East China Sea. The main source of the spat is a group of uninhabited islets. The Senkaku Islands are administered by Japan, but also claimed by China and Taiwan where they are known as Diaoyu and Tiaoyutai, respectively.

Beijing claims nearly all of the South China Sea, including small islands hundreds of kilometers from its southern coast. Other Asian nations, including Brunei, Malaysia, the Philippines, Taiwan, and Vietnam, also have claims to parts of the waters. China has sought to bolster its presence by building on islands and reefs in the South China Sea, a key shipping lane believed to be rich in oil and gas deposits.

The uninhabited Senkaku Islands in the East China Sea are claimed by Japan, China and Taiwan

Speaking at an event for business leaders in Tokyo, Foreign Minister Kishida said many countries were nervous about what he called, "a rapid and opaque increase in (China's) military spending and unilateral attempts to change the status quo in the East and South China Seas under the aim of building a strong maritime state."

The issue is expected to be broached when Kishida travels to China to meet with his Chinese counterpart Wang Yi later this week.

"Through candid dialogue with the Chinese side, I want to get the wheel turning to create the Sino-Japanese relations that are suitable for a new age," he said.

nm/jlw (Reuters, dpa)