Busia Senator Okiya Omtatah has challenged President William Ruto to table evidence to support his claims on corrupt judges.
President Ruto on Tuesday alleged that some judicial officials were colluding with cartels to stall his legacy projects.
"I want to announce here that a few people with vested interests who are beneficiaries of corruption in NHIF are now ganging up with corrupt judicial officers to stall reforms so that fake hospital claims will continue," Ruto said in his address at a burial in Nyandarua.
"I want to assure you that this will not happen in Kenya again, and we will stop it."
Omtatah in a rejoinder refuted the claims, saying he has not bribed any judge in the cases he filed in court challenging new government policies.
In a statement on Friday, he also stated that he is not aware of any bribed judge, adding that "I am not so morally deprived that I can do so".
"His Excellency the President has a right under the law to be heard, and he also has a right to protest just as he has done, and he has access to intelligence, which other Kenyans and I don't have," he said.
"I look him straight in the eye and challenge him to table the evidence of bribe-taking against any judge or bribe-giving he has against any litigant and let the chips fall where they may."
Describing the President's remarks as a "most unfortunate, reckless, misguided and unconstitutional", Omtatah said it would be a "grave matter" in case Ruto lacks evidence to support the allegations.
Omtatah also asked the President to apologise to the judiciary, to the petitioners against his projects and to Kenyans in general.
"The President should immediately take a deep breath, and reflect on the all-important office he occupies in the Kenyan State, as our Chief Executive, and unreservedly apologise to the judiciary," the Senator said.
"He should also seek forgiveness from the diligent public-spirited Kenyans and institutions that have challenged his pet projects in court, and to the general public."