Lorenzo Roca of cleaning firm Chiarissima said an employee was "just doing her job" when she mistook Sala Murat's artwork made from newspaper, cardboard and cookie pieces for trash left behind by workers setting up the Mediating Landscape exhibition at the gallery in Bari, the BBC reported Friday.
Roca said the company's insurance will cover the estimated $13,722 value of the lost art.
Security workers arriving for duty Wednesday morning noticed the works were missing.
"We are obviously very sorry for what happened," city marketing commissioner Antonio Maria Vasile said. "It's clear the cleaning person did not realize she had thrown away two works and their value. But this is all about the artists who have been able to better interpret the meaning of contemporary art, which is to interact with the environment.
"In any case, the insurance will cover the damages caused," Vasile said.