Among them are MP Dilum Amunugama, forme governor Tikiri Kobbekaduwa and local government representatives.
However, none of the leaders or senior members of the SLFP are in attendance.
General secretary of the party Anura Priyadarshana Yapa has banned SLFP politicians from participating in meetings organized by other parties.
However, the party has reportedly taken no decision with regard those who violate the decision.
Former ministers Dinesh Gunawardena and Wimal Weerawansa, former provincial minister Udaya Gammapila are also attending.
Gunawardena has told BBC Sandeshaya that 87 UPFA local government members participated.
Addressing the rally, Gammanpila said there was an attempt to take Mahinda and Gotabhaya Rajapaksa to court, adding that a former president cannot be taken to court.