The airport was built on a former swamp.
"The cracks do not appear in runways and pose no safety threat to aircraft," Somchai said.
The airport's two runways are each served by more than 10 taxiways, and any closures would not cause delays in air traffic, he added.
The cracks were made public by a panel set up by the National Legislative Assembly to inspect the airport's construction.
String of problems
Since opening, the airport which boasts the world's single largest terminal, has faced problems with its baggage handling system and computerised check-in services.
It also underestimated the need for public toilets and the authorities have since earmarked $1 m to build 20 new washrooms.
There have also been complaints about the lack of seating in departure areas, inadequate air-conditioning and paintless walls, columns, and structures.
Suvarnabhumi airport was heralded as one of the crowning achievements of Thaksin Shinawatra, Thailand's deposed prime minister.
Since he was ousted in a September 19 coup, the airport has become a focal point of corruption investigations into Thaksin's administration.