TAIPEI, Apr. 1 (Reuters) - Former Taiwan president Ma Ying-jeou left on Monday for an 11-day trip to China where he is expected next week to have his second meeting with Chinese President Xi Jinping, at a time of simmering tensions across the Taiwan Strait.

Ma, president from 2008 to 2016, last year became the first former Taiwanese leader to visit China. Since the defeated Republic of China government fled to Taiwan in 1949 after losing a civil war to Mao Zedong's communists, no serving Taiwanese leader has visited China.

China considers democratically-governed Taiwan its own territory, and has ramped up military and political pressure to assert those claims.

Ma met Xi in Singapore in late 2015 for a landmark summit shortly before the current Taiwan president, Tsai Ing-wen, won election.

Ma and China's government have not confirmed the meeting with Xi, which has been widely reported in Taiwanese media. Three sources familiar with Ma's trip, speaking on condition of anonymity given the sensitivity of the issue, told Reuters it was expected to take place in Beijing next Monday.

"This is a trip of peace as well as of friendship," Ma told reporters in brief remarks at the airport in Taiwan before flying to the southern Chinese city of Shenzhen in Guangdong province.

Ma added that he hoped to convey a message that Taiwan's people love peace and hope to avoid war.

China's Taiwan Affairs Office, which calls him "Mr. Ma Ying-jeou" rather than former president given neither the Chinese nor Taiwanese government recognise each other, would only say last week when asked about a meeting with Xi that it wished Ma a smooth trip.

Ma's office said while in Guangdong he will visit Chinese electric vehicle giant BYD (002594.SZ), opens new tab and Tencent (0700.HK), opens new tab, the world's largest video game company and operator of China's WeChat messaging platform.

Ma remains a senior member of Taiwan's main opposition party the Kuomintang (KMT), which in January lost for the third time in a row the presidential election, but has no official party position.

The KMT advocates close ties with China and dialogue, but strongly denies being pro-Beijing.

Tsai and her ruling Democratic Progressive Party have repeatedly offered talks with China but been rebuffed, as Beijing views them as dangerous separatists.

Tsai says only Taiwan's people can decide their future. Her government strongly objects to China's sovereignty claims.

Photo from Reuters