The mission, consisting of the United Nations, the European Union and 15 other partners, has also warned against the president's term being extended.

Mohamed Abdullahi Mohamed - known by the nickname Farmajo - was elected as president in 2017.

Somalia's electoral process is a complex compromise that sees clan elders select delegates, who in turn form electoral colleges that determine who is elected president. It has been marred by allegations of vote-buying.

Unsom members said on Thursday that the future election model should "enable the broadest possible participation" and "result in peaceful election of leaders who have broad legitimacy".

Somalia's government committed in October to pass two crucial electoral bills by December to guarantee universal suffrage, as well as a 30% quota for the representation of women in parliament.

But debate on the bills has been marred by divisions and there are concerns about financing of the polls.

The country also lacks a legal framework on relations between the central government and federal states.