Mahama has been helping to entrench democracy and stability in Africa.
He is leading the Commonwealth Observer Group to report on the elections in Liberia.
The team will check compliance with electoral laws.
As former Chair of the ECOWAS Authority of Heads of State and Government, Mahama has been celebrated for his commitment to ensuring the stability of the sub-region and the continent generally.
In a Facebook post, he said he has called a meeting of Heads of all the Observer Missions ahead of Tuesday’s election.
Liberia votes
In landmark elections slated for October 10, Liberians will vote in the country’s third postwar presidential and legislative races.
Incumbent Ellen Johnson Sirleaf — Africa’s first female president — is ineligible to run because of constitutionally mandated term limits. So January 2018 will mark the first time in recent memory that a democratically elected Liberian president will hand power to a similarly elected head of state.