Former President John Dramani Mahama has expressed optimism about the future of the National Democratic Congress, saying it will "bounce back."

In a tweet Friday, the former Ghanaian leader appealed to party supporters to remain calm as functionaries diagnose the cause of the December 7 re-election debacle.

"The NDC will bounce back," he tweeted, adding the "cause of our loss is multifaceted."

Former President Mahama's defeat in December 7 presidential poll has confounded NDC functionaries and supporters who were convinced about his victory.

Some pollsters had predicted his victory because of the glamorous manner his campaign was organised. Giant billboards were erected and positioned at vantage points displaying varying messages.

"Changing lives and transforming lives" was the key mantra of the John Mahama 2016 campaign.

But at the close of polls, his main opponent then New Patriotic Party Presidential Candidate, Nana Addo Dankwa Akufo-Addo, was declared winner by the Electoral Commission.

Out of the 273 of the 275 constituency results declared, the former President polled 4,701,162 representing 44.40 percent with the now President Akufo-Addo recording 5,697,093 which was 53.80 percent of valid votes cast.

Explanation for the NDC's defeat has varied resulting in the decision to set up a fact-finding committee headed by Professor Kwesi Botchwey.

A meeting of the Committee with party executives in the Eastern Region resulted in clashes after some supporters had demanded the Regional executives be exempted. They accused of embezzling funds meant for the party's campaign.

Commenting on his defeat for the first time, Mr Mahama said so many factors were responsible for his defeat - factors he never mentioned.

"We need calm nerves and hard work to strengthen the base of the party," he said.