The fire erupted at a landfill in the municipality of Rynholec shortly before 7 pm local time, sending thick plumes of black smoke visible from the Czech capital.
The blaze covered an area of at least 450 square metres of the landfill, which is five metres high, according to local media.
Fifteen firefighters have sustained light injuries while working to contain the fire.
Authorities expect it will take several days to fully extinguish the flames.
Residents in the area have been advised to keep their windows closed as a precaution against the heavy smoke.
