The Italian Communist Party wound up a three-day emergency meeting yesterday with renewed demands for its participation in a six-party national coalition that are likely to increase-the difficulties of solving the current government crisis.

The meeting of the Communists' 184-member Central Committee ended with an apparently unanimous endorsement of Thursday's 45-page speech by party leader Enrico Berlinguer.

Berlinguer had repeated party demands for a role in an emergency government, sharply criticized the ruling Christian Democrat's refusal so far to upgrade the role of his party, and suggested that if compromise proved impossible, elections could be avoided by the formation of a coalition government that for the first time in 35 years would not include Christian Democrats.

The uncompromising tone of the Communist meeting is seen as a sign that the crisis will be a long one. The session coincided with the conclusion of the fruitless first round of political negotiations by Premier-designate Giulio Andreotti, whose previous government resigned Jan. 16.

The ruling Christian Democrats have so far said they can go no further than to offer the Communists a strengthened and better implemented emergency program to replace the one worked out by Italy's six traditional parties last July.

The second-place Communists virtually brought down the minority Andreotti government when they ended an 18-month-old policy of giving it crucial parliamentary support.

Berlinguer indicates that the Communists' minimum demand is a new minority Christian Democrat government supported by a "negotiated, recognized and explicit" legislative majority including the Communists.

Socialists, Republicans and Social Democrats last week all supported Communist demands for some change in the political framework. All three favor giving the Communists greater direct responsibility.

The Christian Democrats' position at present is that official recognition of Communist inclusion in the legislative majority is politically unacceptable. The Christian Democrats ran their 1976 election campaign on a pledge to keep the Communists out of the government and many Italians believe an official Communist role in the majority would be the first step toward full government participation.

Christian Democratic reluctance to increase the already substantial Communist role here is thought to have been somewhat stiffened by a State Department declaration earlier this month expressing opposition to greater Communist influence.