Sputnik Kazakhstan reports with reference to the Khabar 24 TV channel.
It is noted that they are suspected of price fixing.
"If the guilt is confirmed, they will face serious fines," the message says.
On January 5, it was reported that the director of a gas processing plant in the city of Zhanaozen in western Kazakhstan, Nakbergen Tulepov, was detained amid protests over rising gas prices.
On January 6, it became known that the government of Kazakhstan introduced temporary state regulation on the sale of liquefied petroleum gas, gasoline and diesel.
Later, the Agency for the Protection and Development of Competition of Kazakhstan announced that the actions of the largest sellers of liquefied gas recorded signs of price collusion.