The move, police officials said, was necessitated because the Samagi Jana Balawegaya was planning to hold the protest without seeking prior approval.
The family, which consists of a 61-year old woman, her 34-year-old daughter and her two children and they had entered Sri Lanka on May 6 with the help of fishermen.
Lanka police arrests man for protesting road closure for passage of Chinese defence minister's convoy
Ajith Rohana was seen encouraging the motorists to honk in protest when the police closed the road for the vehicular movement of the Chinese minister at a busy junction in Colombo.
Large crowds of shoppers were seen at most malls without wearing face masks or maintaining social distancing as is required by the health guidelines.