Comoros President Azali Assoumani has put his son, Nour El Fath, in charge of coordinating government affairs as he reshuffled his cabinet following a tense January election that his opponents alleged was tainted by voter fraud.

One person was killed and at least 25 injured in violent protests in the country, a group of three islands off the coast of Mozambique, after the election body declared Assoumani re-elected to his fourth five-year term.

Political analysts, opposition leaders and local media said Assoumani appeared to be preparing El Fath, a 40-year-old with a background in finance and who has worked as senior economic adviser to the president since 2019, to replace him.

Assoumani announced his cabinet late on Monday. He made Ibrahim Mohamed Abdou Razakou finance minister, Said Omar Houmadi justice minister, and reappointed Youssoufa Mohamed Ali as defence minister.

Mohamed Jaffar Abbas, the head of the coalition of opposition parties, said it was clear Assoumani was "trying to build a dynasty".

"(Assoumani) speaks of renewal, but let's not forget that before his son, it was his nephew who occupied the same position of secretary general of the government," he said.

Comoros, with a population of about 800 000, has experienced around 20 coups or attempted coups since winning independence from France in 1975 and is a major source of irregular migration to the nearby French island of Mayotte.

Constitutional reforms in 2018 extended a requirement that the presidency rotate among the three main islands of Comoros from every five years to 10.

El Fath would therefore not be eligible to replace his father at the end of the presidential term in 2029 unless the constitution were changed again.