Public Services Association president Watson Duke, is to face at least one charge under the Sedition Act.
National Security Minister Stuart Young disclosed at Thursday's post Cabinet media briefing that he was, shortly before, informed that the Director of Public Prosecutions, Roger Gaspard, has issued instructions to the Trinidad and Tobago Police Service to lay at least one charge against Duke.
Duke was arrested Monday to face questions over statements he made publicly several months ago.
The union boss has been in hospital the past two days, after falling ill while detained.
Young denied Government had any prior knowledge of Duke's arrest, saying it was entirely the work of the TTPS.
He also refuted some claims that freedom of speech was under attack and that Government was seeking to amend the Sedition Act.