An anti-hijacking and hostage rescue squad of army commandos was already at the Rupavahini state television network to free Labour Minister Mervin Silva who had allegedly stormed the studios and attacked journalists, officials said.
"The minister is being held in an office by the staff," the television said in a statement broadcast while interrupting their regular programming.
Witnesses said the commandos were at the premises to take action if ongoing negotiations with the rebel employees failed to secure the release of the minister and his team.
Police announced over the television that they "arrested" Silva's son who had taken part in the alleged assault and urged employees to remain calm.
Silva's son had earlier been ordered by court to stay away from night clubs after several brawls.
The state broadcaster showed footage of Silva's son being escorted out of a room surrounded by uniformed police as employees booed and punched the air with their fists.
Police and politicia