The push by Azimio to have perceived weaker candidates step down in favour of stronger ones is threatening efforts by the alliance to win votes.
Some politicians allied with the coalition are against the idea and this is likely to hurt its flagbearer Raila Odinga's campaigns.
Raila is hoping to bag most of the 2.61 million votes in the five counties in Western - Kakamega, Busia, Bungoma, Vihiga and Trans Nzoia. He won a majority of the votes in the region in 2017.
Defence Cabinet Secretary Eugene Wamalwa, who is among those spearheading Azimio campaigns in the region, and former Lugari MP Cyrus Jirongo, are among key Raila allies opposed to the push by ODM leadership to zone the region.
Kakamega Governor Wycliffe Oparanya has indicated that there was an agreement for ODM to control Kakamega, Vihiga and Busia counties and leave Trans Nzoia and Bungoma to the Democratic Action Party of Kenya (DAP-K), which is associated with Wamalwa, to try and neutralise Moses Wetang'ula's Ford-K in Trans Nzoia and Bungoma.
However, Wamalwa has been categorical that no such arrangement was reached by Azimio parties.
"Zoning was not among the issues that were discussed during the Azimio Council meeting held at KICC. Therefore, no candidate will be asked to drop their bids in favour of another," Wamalwa told The Standard.
The CS, while on a tour of Busia County on Saturday, assured DAP-K candidates no one will force them to quit in favour of their ODM counterparts.
"What was discussed during the Azimio meeting revolved around formulating realistic strategies to guarantee the coalition and its flagbearer many votes and elective seats in the August elections," Wamalwa said.
Wamalwa said they are determined to ensure Raila bags at least six million votes in 11 counties in Western and Nyanza to give him an edge over his main challenger William Ruto of the United Democratic Alliance (UDA).
"That is the reason we want to mount serious campaigns across Western Kenya and urge voters to come out in large numbers to cast their votes for Raila," said Wamalwa.
“Pollsters have ranked the former PM ahead of DP Ruto. However, we must remain focused and vote for Raila as a region so we can be part of the government that will be formed after August."
Oparanya has engaged in vigorous campaigns over the last week, popularising Raila and Azimio in the 12 sub-counties in Kakamega. Even then, one thing has been clear; Oparanya, a deputy party leader in ODM, has largely been moving around with members of the orange party, pointing to cracks in Azimio campaigns in the region.
Jirongo and Wamalwa have not been seen in the rallies the governor has organised in the recent past.
According to Jirongo, ODM ought to field candidates in Nyanza and let other Azimio affiliate parties have candidates for governor, MP, senator, woman rep and MCA seats take control of Western.