The workers walked out Thursday and Sunday without the backing of their FLP trade union, ANSA reported Tuesday.
The Ministry of Culture said Tuesday it would "pay the outstanding arrears of wages to date from January."
Officials in Rome's tourism sector said the closures hurt businesses' income for those two days.
"In a country like Italy, tourism activities should be considered essential public services," said Bernabo Bocca, head of the hoteliers' association Federalberghi.
Exploding whale video goes viral on Internet
Reindeer recovered after escaping from Santa during lighting ceremony