Italian Premier Giulio Andreotti today handed in the resignation of his minority Christian Democratic government after losing the parliamentary support of the powerful Communist Party.

Andreotti's action sets off what is expected to be a long, drawn-out political crisis that could force Italians to the polls two years before the next scheduled national vote.

At 6:30 p.m., Rome time, Andreotti handed the resignation of his government to Socialist President Sandro Pertini. After constitutionally required consultations with the representatives of Italy's 10 parties, elder statesmen and parliamentary leaders, Pertini is expected to ask Andreotti to try to form another government, perhaps as early as this weekend.

It will be a major test of skill for the 60-year-old veteran politician. Andreotti's own party, the ruling Christian Democrats and the Communists, who brought his Cabinet down when they withdrew their parliamentary support last week, are currently at loggerheads on a series of major issues, including that of the Communists' bid for membership in a "national unity" government.

The Christian Democrats have said repeatedly they will not consider upgrading the Communist's present political role here. Since last March, the West's most powerful Marxist party has been -- together with the Christian Democrats -- a formal member of a five-party alliance that gave Andreotti's minority government the necessary parliamentary support.

The Communist's decision to pull out of the alliance reflected their growing conviction that their semigovernmental status of influence without Cabinet posts was simply not paying off. They have accused the Christian Democrats of mismanagement, delay and disloyalty.

Although the Communists claim they do not want early elections, they appear increasingly willing to accept the risk of a new vote rather than to continue in their present and ambiguous role.

When he went before parliament Monday to announce his decision to resign, Andreotti extolled the accomplishments of the five-party alliance, which he said include reducing inflation from 23 to 12 percent, a balance of payments surplus, the accumulation of $10 billion of foreign currency reserves and the passage of several key reform bills.

But Communist floor speaker Alessandro Natta insisted yesterday that the alliance had been eroded and that another solution, preferably that of Communist membership in a new government, would have to be devised.

A key role in the coming weeks of crisis will doubtless be played by the Communists' smaller Socialist allies, who like Italy's other small parties, are opposed to elections at this time.

The Socialists have been counting on this June's elections for a European Parliament to boost their national and international standing sufficiently to allow them to better compete with both the Communists and the Christian Democrats.

The fall of the Andreotti government comes at a time of renewed terrorist violence, which in the last week took the lives of a 46-year-old Genoa union official and of a 36-year-old Milan magistrate who was involved in antiterrorism investigations.

But most Italians appeared untouched by the crisis, the 36th in 34 years. In Italian politics a government crisis is normally less traumatic than elsewhere, since it regularly occurs whenever Italy's ill-matched parties find it too difficult to govern.

This time, however, the situation could be more dramatic. Over the years the Italian political situation, with its two diametrically-opposed superparties, has been drawing ever closer to a total impasse.