Taiwan has sentenced a retired senior military intelligence officer to three years and six months in jail for leaking classified national secrets, a court said Wednesday.

Pang Ta-wei, formerly of the military intelligence bureau, was convicted by the High Court Tuesday of leaking sensitive military intelligence in a book he published in Hong Kong in 2010.

"What he did, identifying intelligence sources, organisations and other agents, has gravely compromised national security," high court spokesman Hung Kuang-tsan told AFP.

The former colonel will be allowed to appeal, but it was not immediately clear whether he will do so.

The 64-year-old had pleaded not guilty, arguing that the information he cited in this book, the second he wrote, had been reported by local media before, Hung said.

According to the Taipei-based China Times, Pang described his role in the recruiting in 1992 of Liu Liankun, then a major general in the People's Liberation Army, in what is believed to have been the most successful counter-intelligence programme ever launched by Taiwan against China.

Liu reportedly had provided confidential data to Taiwan during the 1990s and became the highest ranking Chinese military officer to be accused of spying for Taipei. He was executed in 1999, according to reports.

Pang had been convicted and sentenced to 18 months on charges of leaking classified military secrets in his first book published in 2004, which was conditionally suspended for four years.

Taiwan and China have spied on each other ever since they split in 1949 at the end of a civil war. Beijing still regards the island as part of its territory awaiting reunification, by force if necessary.