Italian Foreign Minister Paolo Gentiloni said it was hard to speculate who was behind the abductions.
However, many Italians work in oil, gas and construction sectors in Libya, which was an Italian colony in the early 1900s.
The four men were taken west of Tripoli, the foreign ministry said Monday. Italian media reported that the four workers were returning from Tunisia when they were abducted.
A crisis team has been activated to assist and coordinate efforts to free the employees of the Bonatti construction company, who were working for Melitha Oil and Gas, the ministry said. According to military sources quoted by al Jazeera, the kidnappers could be militants close to Jeish al Qabali, the army of tribes hostile to Fajr Libya, the Islamist faction that has imposed a parallel government in Tripoli opposing the one in Tobruk, the only one recognized by the global community.
The country is beset with warring factions four years after the civil war that ousted leader Muammar Gaddafi.
Italy closed its embassy in the North African country in February when it called on Italians to leave because of the dangers to foreigners.