Taiwan Semiconductor Manufacturing Company alleges a former employee and two current staff may have “unlawfully obtained” trade secrets, the high prosecutors office’s intellectual property branch said.

The information relates to the firm’s “national core technology”, they said.

TSMC made the discovery in July after detecting “unusual access to internal personnel files”, the prosecutors said.

After speaking to witnesses and collecting evidence, prosecutors said the three defendants were “strongly suspected” of violating the National Security Act.

TSMC is the world’s largest contract maker of chips and counts Nvidia and Apple among its clients.

In a statement, it said it had taken “strict disciplinary actions against the personnel involved” in the “potential trade secret leaks”.

“As the case is now under judicial review, we are unable to provide further details at this time,” TSMC said.

The company did not provide details about the technology involved in the suspected leaks.