The incident occurred around 3 am on Sunday.
It gathered that some hoodlums suspected to be political thugs allegedly set a section of the building ablaze along with some election materials.
An electric generator owned by the commission was also burnt.
Some of the staff at the building, however, fled the scene.
Confirming the incident to NAN, Mr. Olusegun Agbaje, the Osun Resident Electoral Commissioner, said it was a minor incident.
Agbaje said the fire did not affect Saturday’s election results.
“What happened was purely criminal and does not have any political undertone.
“Some of our staff heading to the office met some yahoo-yahoo boys on their way.
“On getting to our office, they discovered that the hoodlums were after them.
Read also: I will lead protest if INEC failed to…
“Our staff dropped the election materials and the generator with them and fled.
“The hoodlum thereafter poured the petrol on the generator on the election materials and set them ablaze.
“What I heard was that the hoodlums said someone called them a nickname which angered them but whosoever called them the nickname is not one of our staff.
“But I can authoritatively confirm to you that the election results were not affected and the building was not razed,’’ Agbaje said.
The REC added that the collation officer for the Local Government was already at the INEC State Headquarters collation centre in Osogbo with the election results.
Agabaje also said that no lives were lost. (NAN)