TAIPEI (AFP) - A Chinese farmer who was twice jailed for illegally entering Taiwan "to pursue democracy" has been arrested again after a four-hour swim to the island, officials said on Thursday.

The 38-year-old from Sichuan province in south-west China was caught on Wednesday as he came ashore on Taiwanese-controlled Kinmen island, a few kilometres from China, the local county government said in a statement.

The man said he kept trying to get to Taiwan because he wanted to "pursue democracy and freedom" despite failed attempts in 2003 and 2009 that both led to time in jail in China, the statement added.

He had taken a train from Sichuan to Xiamen, a city on China's south-east coast, where he made his third swim across the Taiwan Strait.

The man, who has not been named, was sent to the local district prosecutor's office for trying to enter Taiwan illegally and will be deported to China.