Taiwan's coast guard ramped up patrols over the weekend around outlying islands that have seen increased presence of Chinese vessels, the agency said Sunday, the day before Lai Ching-te's inauguration as Taiwan's new president.

China claims democratic Taiwan as part of its territory, maintaining a near-daily military presence with frequent appearances of fighter jets, drones and naval ships around the island.

It has also in recent months deployed Chinese coast guard ships around Kinmen, an outlying island administered by Taipei located just five kilometres (three miles) from the Chinese city of Xiamen.

Taipei's Coast Guard Administration said Sunday it had sent personnel to "patrol all hours of the day and night" around Taiwan's three major outlying islands: Kinmen, Matsu and Penghu.

"In order to ensure the security of the sea area and border safety during the inauguration ceremony, the Ocean Affairs Council's Coast Guard Administration's Kinmen-Matsu-Penghu Division once again implemented a powerful patrol operation... to closely monitor suspicious targets," it said in a statement.

"The Kinmen-Matsu-Penghu Division said that the national security work will not slacken during the important celebrations," it added.

Kinmen has been the site of heightened tensions after Lai -- who China has branded a "dangerous separatist" -- was elected in Taiwan's January elections.

A deadly fishing incident in February involving a Chinese speedboat kicked off a row between China and Taiwan, which has yet to be resolved.

The boat was carrying four people and capsized on February 14 near Kinmen while Taiwan's coast guard was pursuing it, leaving two dead.

Taipei's coast guard had defended its actions, saying the boat was within "prohibited waters" and zigzagging before it capsized, but Beijing has accused Taipei of "hiding the truth" about the incident.

At least five formations of official Chinese ships have briefly sailed through Kinmen's restricted waters this month.

On the eve of Lai's inauguration, Taipei's defence ministry said it had detected seven Chinese aircraft and seven naval vessels around Taiwan in the 24-hour period leading up to 06:00 am on Sunday (2200 GMT Saturday).

Across the strait in the Chinese seaside city of Pingtan -- also home to a military base -- AFP reporters saw at least two military transport helicopters fly overhead Sunday morning.

Lai, like outgoing President Tsai Ing-wen, rejects China's claims over Taiwan.

He has vowed to defend the island's democracy while appealing to Beijing to resume high-level communications -- severed since 2016.

Speaking at a reception for international delegations attending the inauguration, Lai said Sunday evening he was "truly grateful" for the show of support for the island.

"We will continue to walk on the path of democracy and we will continue to engage with the world to make Taiwan stronger," he said in a brief speech.

"We hope to continue to have your strong support."