The statement from the president’s office late on Wednesday did not specify why Hachani was removed.
Hachani had taken office on August 1 last year, replacing Najla Bouden, who was also dismissed without an official reason by Saied, Al Jazeera reported.
A few hours before he was dismissed, Hachani said in a video message that the government had made progress on a number of issues despite global challenges, including securing the country’s food and energy needs.
His replacement, Kamel Madouri, had only taken on the social affairs portfolio in May.
The sacking comes ahead of Tunisia’s October 6 presidential election, in which Saied is seeking another term, and amid widespread discontent over continuing water and electricity outages in many parts of the country.