The presidency said in a statement that Khaled Shili would be the new defence minister and Mohamed Ali Nafti the foreign affairs minister.
Saied earlier this month sacked Prime Minister Ahmed Hachani, replacing him with Kamel Maddouri, the social affairs minister.
The abrupt reshuffle replaced 19 ministers and three state secretaries, days after Saied sacked the former prime minister ahead of presidential elections on October 6.
“This morning, August 25, 2024, the President of the Republic has decided to make a governmental change,” said the statement, without further explanation.
Saied, 66, was democratically elected in 2019 but orchestrated a sweeping power grab in 2021 and is now seeking another term in the upcoming elections.
He has referred to his candidacy as part of “a war of liberation and self-determination” aiming to “establish a new republic” while a number of his political opponents are currently in jail or being prosecuted.
Earlier this week, Human Rights Watch (HRW), a global watchdog, said Tunisian authorities “have prosecuted, convicted or imprisoned at least eight prospective candidates” for the October vote.