The biggest opposition party is holding its internal polls to elect a flag bearer for the 2024 elections as well as parliamentary candidates on that date.
Mr Mahama is seeking a comeback, both as a candidate and president.
Speaking to party supporters and delegates in Bimbilla, Northern Region, as part of his campaign tour, the former president said: “Everyone has his supporters; there’s no point saying this person supported the winning team, so, we will stay aside.”
“All of us are NDC. Let’s support each other after the primaries,” he urged.
Mr Mahama was defeated in 2016 as an incumbent president and also lost the 2020 polls as an opposition candidate.
Per Ghana’s 1992 Constitution, which places a two-term limit on the presidency, Mr Mahama has one more term to do.