A Taiwanese businessman has been detained for allegedly spying for China, prosecutors said on Thursday, in the second espionage case to hit the island in less than a week.

The man, identified by his surname Cheng, was allegedly recruited by China when he moved to the southeastern costal province of Fujian to do business a few years ago, prosecutors said.

Cheng was accused of trying to lure a former classmate, who is now a military officer, to meet with Chinese officials abroad for money but the officer turned him in to Taiwanese authorities, they said.

Prosecutors raided Cheng's office and homes in southern Taiwan on Wednesday and took him into custody along with his wife early Thursday on suspicion of violating national security law.

This marked the second spying case in less than a week, after two former agents were indicted on Monday on charges of collecting information for China.

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

Since 2008, the two sides have seen significant progress when Ma Ying-jeou of the China-friendly Kuomintang party became Taiwan's president.

But Ma, who was re-elected for a second term in January, has said Taiwan should strengthen its defences against Chinese espionage following a string of spy scandals showing intelligence gathering has continued.

This year an ex-agent was arrested for allegedly luring his colleagues to China to force sensitive information out of them while an air force captain was accused of leaking classified data to Beijing via his China-based uncle.

Taiwan's military court last year sentenced an army general to life in jail for spying for China in the island's most serious espionage scandal in recent years. - Sapa-AFP