Officials searched 34 locations and questioned 90 people this month as part of an investigation into 11 Chinese firms, Taiwan's Investigation Bureau said.

"The high-tech industry is the lifeblood of our country's economy, and companies with semiconductor technology and related industrial chains maintain our economic strength," the bureau said in a statement.

"Talents in related industries have therefore become the targets of poaching by Chinese firms."

Shanghai-based SMIC was suspected of "illegal acts" in northern Hsinchu, home to an industrial park dubbed Taiwan's Silicon Valley, the bureau said.

"The company used a Samoan business as a cover to come to Taiwan to set up a branch (or branches) and poached talents under the guise of an 'overseas Chinese and foreign investor'," the bureau added without providing further details.

Investigators were also looking into other chip firms including Shenzhen Torey Microelectronics Technology Co. and Clounix.

Taiwan is a chip powerhouse, producing more than half of the world's semiconductors -- including almost all high-end chips.

China claims the self-ruled island as part of its territory and has not ruled out the use of force to bring it under its control.

Taipei has warned that Beijing is stepping up its efforts to poach the island's high-tech talent.

In January, the Taiwan branches of three Chinese companies were indicted for recruiting engineers illegally and stealing industry secrets.

China has been seeking in recent years to shore up its self-reliance in the increasingly competitive semiconductors sector, and SMIC is the country's chipmaking champion.

Despite Beijing pouring tens of billions of dollars into the domestic chip industry, the technical performance of SMIC and Chinese firms still lags that of Taiwanese giant TSMC.