Tokyo: A Chinese navy survey vessel on Sunday entered Japan's territorial waters near islands close to the southwestern prefecture of Kagoshima. It is the latest confirmed sighting of a Chinese ship in the area since December, quoting Japan's Defence Ministry, Kyodo News reported.

According to the Japan-based news agency, a survey ship crossed into Japanese waters from southwest of Yakushima Island in the prefecture at around 2:30 am, marking the seventh entry by a Chinese survey vessel into waters off Kagoshima since November 2021.

Japan expressed concerns to China regarding the ship's actions. The vessel at around 4:00 am, sailed out of the territorial waters near Kuchinoshima Island, about 50 kilometres southwest of Yakushima, the Kyodo News reported.

Chinese ships have often entered Japan's territorial waters or sailed through adjacent areas, most notably near the Senkaku Islands, a group of East China Sea islets controlled by Japan but claimed by China under the name Diaoyu.

China's growing military presence in the South and East China seas has been a source of friction with some countries in the region due to China having overlapping territorial claims with neighbours, according to Kyodo News.

Survey vessels are often used to conduct research, such as determining underwater topography for submarine navigation, it said.

The media recently reported that Japan is set to ramp up patrolling of its territorial waters amid the increasing presence of Chinese vessels in and around the waters near the Senkaku Islands, known as the Diaoyu islands in China.

The Fumio Kishida government has developed a policy to boost the country's Coast Guard capabilities, including patrolling its waters by ship and aircraft, Japan's NHK World reported.

The Japanese media said this development follows an increase in China's maritime activities last year near the Senkaku Islands in Okinawa Prefecture.

The Senkaku Islands are a group of islands in the East China Sea. They are located northeast of Taiwan, east of China, west of Okinawa Island, and north of the southwestern end of the Ryukyu Islands. Japan maintains they are an inherent part of its territory. Meanwhile, China and Taiwan also claim these islands.

According to NHK, Chinese government ships last month navigated Japanese waters in the area for more than 72 hours. The report added that it is the longest-ever continued intrusion of its kind since the Japanese government purchased some of the islands from a private Japanese owner in 2012.

In December, the Japanese government approved a draft budget for the next fiscal year for a record 114,38 trillion yen (USD 862 billion) with a record-high defence budget in the amount of 6.8 trillion yen.