According to chiefs at Atac, the company that manages Rome's transport network, many employees called in sick after the strike ended at 12.30pm.
“On the same day as the strike, there has been a significant rise in the cases of sickness,” the company said.
While it didn't divulge the exact number of absentees, the company said that the metro's line B is the most affected, with there being “three times the normal number of absentees” among staff manning the line.
As passengers encounter public transport misery for the rest of the day, check-ups would be made on the allegedly sick members of staff at their homes, Atac added.
Italy's public sector is plagued by high absenteeism, with Prime Minister Matteo Renzi vowing to crackdown on the work-shy earlier this year.
Meanwhile, hundreds of municipal police officers in Rome called in sick on New Year's Eve 2014.