Mr Chadchat said according to the report he received, some goods with a phosphorus content, intended for an exhibition in Cambodia, were in the suitcase. It was believed a chemical reaction caused by heat or friction started the fire.
"It was fortunate this happened while the suitcase was not yet loaded on the plane. It would have been very dangerous if the fire broke out while the plane was flying," Mr Chadchat said.
Mr Chadchat said he had ordered an investigation, but did not believe it was an act of terrorism.
It was later reported that the suitcase belonged to Pongkan Kositthammanat, the owner of Pongkan Alliance Co, a supplement food dealer.
Mr Pongkan said he was leaving for Cambodia on Bangkok Airways Flight PG 931. He checked in at the airline's counter at 6.15am and boarded the plane at 8.35am.
The Suvarnabhumi airport has filed a police complaint against Mr Pongkan.
A later report said the airlines' staff quickly put out the fire with an extinguisher. The fire was attributed to a sample of a phosphate fertiliser in the bag.