Roots party leader George Wajackoyah has criticised COTU secretary general Francis Atwoli of lacking a political stand.
Speaking on Monday, Wajackoyah said Luyha leaders are uniting for political gain.
"Atwoli can't stand before Luyhas and tell them that we need unity, when he has been standing with Raila and all of a sudden he has jumped. We shall never follow that example," he said.
"Remove Atwoli away from you, he is going to smear dirt on you that will make us to hate you permanently."
Wajackoyah said Luyha leaders should instead unite to develop the communities in Western Kenya.
He said Atwoli is not and will never be part of the Luyha community.
This is after Atwoli met President William Ruto a few days after giving signals of working with the Kenya Kwanza government.
Atwoli was in Raila Odinga's Azimio La Umoja camp in the run-up to the August 9, general election.
He campaigned fiercely against Ruto's presidency, at one point going on record stating that Ruto will never succeed former president Uhuru Kenyatta.
Atwoli was part of a delegation from the Luhya community that met Ruto at the State House.
Others who accompanied him are Prime Cabinet secretary Musalia Mudavadi, Kakamega Senator Bonny Khalwale, former Kakamega gubernatorial candidate Cleophas Malala and Rashid Echesa.