The unified AIADMK resolved to annul the appointment of VK Sasikala as the party's interim general secretary, party officials said.
It said the party cannot accept anyone else other than its founder, the late MG Ramachandran, and the late chief minister J Jayalalithaa as general secretary.
A meeting of the general council, the apex decision making body of the party, and the executive committee passed a resolution to cancel Sasikala's appointment, sources said.
The meeting also resolved to amend the party's by-laws, indicating that there would be no general secretary in the future.
Party affairs would now be managed by a steering committee, as announced during the merger of the factions led by Chief Minister K Palaniswami and his Deputy O Panneerselvam on August 21.
Tuesday's meeting was the first since the merger of the two factions.
It was attended by, among others, Palaniswami and Panneerselvam and presided over by party presidium chairman E Madusudhanan.