Former Thai premier Thaksin Shinawatra is visiting South Korea to tour a $19 billion river upgrade project which he believes could have averted Thailand's flood disaster, officials said Tuesday.

The fugitive ex-premier, during his private trip from Monday to Thursday, is visiting sites connected with the project to dredge, dam and beautify the South's four major rivers, said officials at Seoul's land ministry.

"Thaksin said he had been thinking a lot about chronic flood problems in Thailand and wanted to see our river projects himself to get some ideas," Go Young-Suk, a ministry official who accompanied him for the tour, told AFP.

"He asked a lot of questions."

Thaksin, in an interview with Tuesday's Chosun Ilbo newspaper, said he would report the outcome of the trip to Yingluck Shinawatra, his younger sister and current prime minister.

He told the paper he drew up a comprehensive flood and drought prevention plan while he was in office, but this was aborted when he was ousted in a 2006 military coup.

"The latest flood damage would have been one-fifth of the current level had my project been implemented as planned," Thaksin was quoted as saying.

The Thai floods have killed more than 600 people and damaged the homes and livelihoods of millions.

The 62-year-old ex-premier lives in exile in Dubai and faces a two-year sentence for graft if he returns home.

Thaksin is travelling with three aides. He is believed to have no meetings planned with senior Seoul government officials during the trip, made at the invitation of a South Korean businessman, said a land ministry spokesman.

The South's "four rivers project" aims to revitalise the Han, Nakdong, Geum and Yeongsan rivers, control flooding and save water. The project, which began in 2009, is expected to be completed in December next year.