Azimio La Umoja One Kenya Coalition is set to hold a meeting in Kibra Constituency on Sunday at Kamukunji Grounds, Kibra constituency.
The coalition said the meeting was to give hope to its supporters in Kibra after Raila failed to clinch the presidency in the August elections.
A number of people have streamed to the grounds awaiting their leaders to address them.
The meeting has come a day before the coalition is set to file a petition at the Supreme Court to challenge the presidential election results which saw Deputy President William Ruto announced as the winner.
Raila claimed that the declaration of Ruto as the president-elect was null and void.
"Let no one take the law into their own hands. We are pursuing constitutional and lawful channels to invalidate (Wafula) Chebukati's illegal and unconstitutional pronouncement. We are certain that justice will prevail," he said.
His legal team is exploring seven crucial grounds to overturn Ruto's win at the apex court.
