Late President Beji Caid Essebsi's son, Hafedh Caid Essebsi, was dismissed as the leader of the Nidaa Tounes party.
The move took place a two-day meeting held by the party over the weekend.
It demonstrates an attempt to carry out reforms within the party that was founded by the late president in 2012.
The party announced a vacancy in the position of the head of the Central Committee and the party’s legal representative.
It was approved after Hafedh Essebsi decided to move to Paris. He has been distancing himself from the Tunisian political scene for about three months.
Kacem Makhlouf was appointed interim leader of Nidaa Tounes’ central committee until a president is elected. Mongi Harbaoui was also dismissed from his position as the party's official spokesman.
Makhlouf is one of the political leaders who supported Hafedh Essebsi against the Hammamet Congress, which is led by Sofien Toubel, Nidaa Tounes’ regional coordinator in Monastir city.
Hafedh Essebsi had been widely accused of autocratic leadership and seeking to inherit his father’s position in power.
Nidaa Tounes, however, suffered a major defeat in recent parliamentary elections, winning only three seats in the legislature, compared to 86 it had won in 2014 polls.
This prompted the party to review its structure and policies and determine the causes of the loss.