Senate Speaker Amason Kingi has urged Investments, Trade and Industry CS Moses Kuria to stop making allegations he cannot substantiate.
Speaking after he appeared before the Senate plenary, on Wednesday, the CS claimed the media was working with cartel companies trying to control edible oils business.
Speaker Kingi told the CS to drop the claims unless he has facts to give to the Senate.
"You are making very grave allegations and the rules that apply in this house is that you be able to substantiate any allegation you make in this house," Kingi said.
"One of the allegations you are making is that there are five companies run like a cartel and that they are sponsoring headlines. Hon CS if you cannot prove them kindly drop them, if you can go ahead and give us factual basis."
The Trade CS's remarks were in response to a question by Laikipia Senator Nderitu Kinyua on the recent media reports over edible oils.
Kuria claimed that five companies that control the trade are using the media to fight the government's effort to bring down the cost of edible oils.
He added these companies have enjoyed monopoly in the business for years and will go to any length to stop it.
"The reason there is an outcry in the media is that there is noise sponsored by companies that have continued to enjoy a monopoly and are using profits they have made historically to fight our efforts to bring down the cost of living. If any other company wants to import the same product it is slapped with a 35 per cent import duty whereas these people pay nothing," he said.
"So the direct nexus between the answer I've given and the question by Senator Kinyua is that the media is working for these cartels who want to lockout everybody and keep prices high and will do anything possible."