Alitalia flights to and from airports across Italy, apart from Venice and Bologna, will be affected, La Repubblica reported.
Anpac, the labour union which has organized the strike, said the action is due to the company's “refusal to sign a commitment to maintain staff levels, without which about a thousand pilots and flight attendants risk losing their jobs.”
They are also concerned that Alitalia will eventually relinquish some of its medium-haul business to its merger partner, Etihad.
The Abu Dhabi-based carrier bought a 49 percent stake in the business last summer.
Meanwhile, pilots for CityLiner, a unit of Alitalia which operates short-haul flights with low passenger numbers from minor airports to Rome's Fiumicino, are protesting against the company's failure to commit to an agreement promising equal pay between them and their Alitalia colleagues.
Alitalia said the strike was "disrespectful to consumers and colleagues, just when Fiumicino is trying to return to normality" after a fire in May closed terminal three, which handles international flights.
Passengers have since faced disruption, as the airport's capacity was reduced to 60 percent. The terminal is expected to reopen at the end of July.