Former Energy Minister Tina Joemat-Pettersson has also resigned from Parliament.
The former minister lost her job when President Jacob Zuma reshuffled his cabinet on Friday, March 31.
She was replaced by Mmamoloko “Nkhensani” Kubayi.
She is the third fired Cabinet Minister to put down the reigns, after Dipuo Peters and former Finance Deputy Minister Mcebisi Jonas.
Parliament spokesperson Moloto Mothapo confirmed the resignation on Thursday.
Meanwhile, former Public Service and Administration Minister Ngoako Ramatlhodi is not resigning, yet.
The former minister told News24 on Thursday that he did not know if he would stay or go.
“I need time to reflect before making a decision. Right now, I’m relaxing and playing my golf,” he said.
He did not know how long he would reflect, he said, but it would not be “for a while”.
Ramatlhodi said he would also need to reflect on whether to attend the motion of no confidence against President Jacob Zuma, to be debated in the National Assembly on Tuesday, April 18.
Both Jonas and Peters’ resignations were effective from March 31.
News24 understands that former Tourism Minister Derek Hanekom, who was also fired, is staying in Parliament.
Mthembu wished all the axed ministers well following their resignations.
They had served with “absolute distinction”, he said.