Lawyer Edwin Sifuna and Bukachi Chapia are embroiled in a fight over who will fly ODM's flag in the Nairobi senator race.
Chapia on Friday claimed he was implored by ODM leader Raila Odinga to step down for Sifuna but declined the request.
"We had a meeting with Raila, Governor Evans Kidero, Lawyer Sifuna and 15 members of my political committee at Capital Hill office."
"The meeting was for me to step down but I disagreed because my new role in the party was not pronounced and guaranteed," Chapia said.
The aspirant, in a statement, said he will pursue legal redress on the matter citing that he had won the ODM primaries fairly.
"It is wrong to be asked to step down. I informed Sifuna that I'll sue him as a person and the ODM party for going against my democratic right in the party."
He argued that Sifuna is being positioned as a public figure who already has a name in the city.
The latter was trounced in the just concluded nominations in his Kanduyi backyard, Bungoma county.
However, Sifuna defended his decision to shift to Nairobi basing it on pressure from his supporters in the capital.
"I have subsequently been petitioned by residents, party supporters, and the party leadership to consider playing in a different position for the team."
"This is why I have accepted the party's nomination as its Senate candidate in the great county of Nairobi," Sifuna said in a statement.
Sifuna said he will embark on a serious grassroots campaign in the capital.
The circumstances under which Chapia was asked to step down are yet to be established.