Several television workers have been attacked following an incident where junior labour minister Mervyn Silva was held hostage by staff of the station after he stormed the newsroom and assaulted its news chief.
Secretary of the workers union P Nandipala said five out of six trade unions were supporting their action with a union aligned to the ruling Sri Lanka Freedom Party not supporting their action.
Sri Lanka's president Mahinda Rajapakse is to meet television worker unions later in the day.
Unions say they want minister Silva removed from his post, for law enforcement authorities to take action against him, ensure the security of workers and compensate those who have already been attacked.
Several state TV journalists have been knifed or assaulted