Two female MPs of the parliamentary bloc of Nidaa Tounes resigned from the party on Monday, bringing the number of those who have resigned to 21 members out of 86.
A resigned member from Nidaa Tounes Walid El-Gallad named the two MPs as Huda Slim and Rabha Bin Hussein.
Tunisian Radio Shems FM quoted El-Gallad as saying that there are eight other members who announced their resignations from the party as a first step.
This leaves the moderate Islamist party Ennahda, previously the minor coalition party, with a parliamentary majority.
The Nidaa Tounes party has been plagued by continuous resignations as a result of internal divisions and the resignation of the former Secretary General Mohsen Marzouk from the party.