The latest spying case comes during a low point in relations between Taiwan and China -- which claims the democracy as its territory -- with Beijing ramping up military and political pressure on the island.

The Taiwanese Ministry of Defence responded on Wednesday to local media reports about a lieutenant colonel surnamed Hsieh, and others, "who allegedly were recruited by China to collect intelligence".

"The Defence Ministry condemns a small number of personnel... who committed such crimes of betraying the people and the country," it said in a statement, mentioning Hsieh by name without confirming or denying his detention.

"In the face of the Chinese Communists' infiltration, the military will continue to strengthen counter-intelligence education and enhance security vigilance," it added.

No details were given about the alleged crime.

The statement came after a report from Central News Agency -- a partially state-funded news outlet -- that said Hsieh had worked for the army's Aviation and Special Forces Command in northern Taoyuan county

He had allegedly gathered and passed intelligence to China via a middleman, CNA reported, citing prosecutors.

He also attempted to recruit active and retired servicemen to develop a spy network, CNA said, adding that prosecutors had launched a probe after receiving a tip.

Hsieh and the alleged middleman were reportedly taken into custody after being questioned by prosecutors, while four retired servicemen also suspected of involvement were released on bail.

Taiwan and China have been spying on each other since the end of a civil war between Chinese nationalists and communists in 1949.

A number of former high-ranking Taiwanese military officials have in recent years been accused of spying for Beijing.

In March, a retired navy rear admiral and a former lawmaker were charged over an alleged bid to build a spy network for China.

And in January, a retired air force major general received a four-year suspended sentence for accepting meals and trips offered by a Hong Kong businessman allegedly acting on behalf of Beijing.