The National Super Alliance (Nasa) is set to hold its first rally in Bomet, a presumed political backyard of Deputy President William Ruto.
On Thursday, Bomet Governor Isaac Ruto denied he had joined the new opposition outfit but confirmed he would host the Nasa team on Saturday.
Mr Ruto has formed his own political party: Chama Cha Mashinani. He criticised President Uhuru Kenyatta and the Jubilee government, saying they had failed to meet the expectations of Kenyans.
The Bomet Governor also denied that he planned to defect from the governing coalition to the new opposition coalition at Saturday's rally in the county.
He said he will be hosting the team to promote democracy.
"The claims that I will join Nasa are incorrect. People are just speculating. I have not made such a statement," Mr Ruto said.
In Nairobi, Nasa management committee began working out the modalities of how the alliance's candidate will be picked.
Senators James Orengo (Siaya) and Johnson Muthama (Machakos) and MPs John Bunyasi (Nambale) and Eseli Simiyu (Tongaren) have been appointed the conveners of the coordinating committee.
The team held its first meeting with the principals on Tuesday to lay out strategies on how to move their agenda forward.
Though Mr Orengo and Mr Muthama previously discharged coalition operations for Cord from ODM leader Raila Odinga's Capitol Hill office, the new team has moved to Mr Orengo's office in the city centre where they are temporarily hosted.
A technical team to assist Mr Orengo's group will be appointed later next week to initiate a thematic approach in the search for a joint presidential candidate.
The four candidates have been consulting and have each agreed to support one another when the team finally settles on a candidate.
Mr Orengo's group will come up with an approach to be used to select or elect the candidate from among the four candidates or from others expected to join the group.
They have also been mandated to complete registration logistics for the new political entity as required by law following the reservation of the name by some supporters of the Amani National Congress.
The team has been mandated to reach out to other leaders including former Cabinet Secretary Charity Ngilu and Baringo Senator Gideon Moi.
Mr Odinga said the new opposition outfit would morph to face Jubilee in the August election.
Mr Odinga said: "It is a vehicle for an alternative accountable, responsible and responsive leadership that will restore hope in self-government among Kenyans".
Additional reporting by Anita Chepkoech.