At the moment of the incident, 374 people were working at the coal mine run by Mittal Steel Temirtau in Karaganda, southeast of the country's capital, Astana.
Rescue work has been obstructed by high gas levels and the high temperature in the mine.
Nazarbayev offered his condolences to the late miners' families and ordered that a commission be set up to investigate the causes of the tragedy and to arrange assistance to the families.
"All Kazakhs empathize at this difficult time with the disaster that has struck the miners of Karaganda," a message from the president said.
The incident in Kazakhstan was not the only one Wednesday. In Ukraine, 13 people died following an explosion at a mine in the east of the country.
A total of 25 miners died after a blaze broke out September 7 in a Russian pit in southern Siberia.
