The dispute over Sondu market boundary escalated as MCAs from Nyakach said the facility is in Kisumu and not in Kericho.
Senator Aaron Cheruiyot last week said that Sondu market belongs to Kericho county.
The Nyakach MCAs said in a press statement that the senator claimed Kisumu county revenue officials have been illegally collecting revenue in the busy market and harassing traders from Kericho.
They said the utterances made by the senator might incite residents of the two counties.
They want the National Cohesion and Integration Commission to take up the matter and the senator to apologise for his remarks.
South East Nyakach MCA Johnson Guya said Cheruiyot's remarks were in bad taste, populist and could easily spark mistrust and unnecessary tension between communities trading in the market.
He said there is evidence that Sondu market is on the Kisumu side of the border.
Guya said traders from Kisumu and Kericho have over the years co-existed in the market without any friction or disputes.
"We call for sobriety and calm over this matter. It's a delicate issue which must be handled with care. Leaders from both sides must desist from utterances that may disrupt the peaceful co-existence of all communities trading at the market".
Guya said records and maps at the Lands department should be used to help resolve the matter.
He was accompanied by North Nyakach MCA Rashid Miruka, Ombeyi's Vitalis Otura, Nyalenda B's Joseph Olale and Kabonyo's Oiko Opete.
Otura said Cheruiyot is a legislator and he knows the procedure of handling such matters.