China claims self-ruled Taiwan as its territory and relations have soured since the island's independence-leaning President Tsai Ing-wen came to power in 2016.

Beijing has in recent years ratcheted up diplomatic and military pressure on Taiwan and the number of warplane flights around the island increased dramatically following last August's visit by Nancy Pelosi, then-speaker of the US House of Representatives.

Taiwan's defence ministry said in a statement that 68 Chinese aircraft and 10 naval vessels were detected near the island between Wednesday morning and Thursday morning.

Taipei had already said some of those planes and warships were heading to an unspecified area of the Western Pacific to "conduct joint sea and air training" with China's Shandong aircraft carrier.

The Shandong, one of two operational aircraft carriers in the Chinese fleet, was detected Monday around 60 nautical miles (110 kilometres) southeast of Taiwan heading into the Western Pacific, Taipei authorities said.

Japan's defence ministry also said Wednesday its navy had detected six ships -- including frigates, destroyers, one fast combat support ship and the Shandong -- sailing through waters some 650 kilometres (400 miles) south of Miyakojima island, east of Taiwan.

It also confirmed that jets and helicopters had been detected taking off and landing from the Shandong.

- 'Grey zone' -

China's military "has been tasked to develop capabilities to take over Taiwan", one expert said.

"Those military exercises are aimed at developing and practising those capabilities," said Bonnie Glaser, a China expert at Washington DC's German Marshall Fund.

"We should expect its trend to continue, with growing pressure on Taiwan."

James Char, a research fellow at Singapore's Nanyang Technological University, said China's military activities around Taiwan -- particularly aerial incursions into the island's air defence identification zone -- had become a "regular occurrence".

But the activities were "all, without exception, operations below the threshold of war and occurring outside Taiwanese territorial airspace", he told AFP.

China has not commented officially on any drills being conducted in the Western Pacific.

- 'Equal treatment for Taiwan' -

And in contrast with the sabre-rattling, Beijing this week dangled the prospect of preferential treatment for people from Taiwan seeking to live, work, study and do business in mainland China.

The series of "opinions" announced by two top Communist Party bodies on Tuesday also urged the coastal city of Xiamen to "speed up" its integration with the Taiwan-administered Kinmen and Matsu islands located a few miles offshore.

At a press conference Thursday, Pan Xianzhang, vice director of the Taiwan Affairs Office of the party's Central Committee, said the goal of the policy was to create a "demonstration zone for cross-strait integrated development".

"The focus is on... taking the lead in implementing equal treatment for Taiwan compatriots and businesses so as to make Taiwan compatriots fully experience the benefits of integration", Pan said.

Cong Liang, vice director of China's National Development and Reform Commission, said at the same briefing that a high-speed rail line should be built across the Taiwan Strait in order to achieve "direct infrastructure connectivity" with the mainland.

China conducted military exercises in April to simulate the encirclement of Taiwan after Tsai met US House Speaker Kevin McCarthy in California.

At the time, Taiwan detected 71 Chinese warplanes in a 24-hour period, matching the record daily high set in December 2022.