A senior Polish Communist Party official today played down Western speculation of an imminent Soviet invasion, but acknowledged that Poland's economic and political crisis has deepened significally over the last two months.

Jozef Klasa, head of the party's information department, would not rule out the possibility of the Soviet Union responding to a request by Polish communists for military assistance, but said he believed Poland will find a solution to the crisis through its own efforts.

Klasa's remarks, at a specially convened press conference, came as the official news media devoted extensive attention to a dramatic appeal to the nation released by the Communist Party's Central Committee following a two-day meeting earlier this week. The appeal warned of possible "economic and moral destruction" unless the widespread industrial unrest of the last five months is brought to a halt.

Polish newspapers have begun reporting warnings by Western leaders of the threat to detente that would result from Soviet intervention here. Newspapers mentioned for the first time today that the Soviet ambassador in Washington, Anatoliy Dobrynin, has been summoned to the U.S. State Department last week in connection with the Polish crisis.

Klasa said reports were being made public so Poles would not have to rely exclusively on foreign broadcasts for information. A reason Klasa did not mention may be that the authorities want their people to appreciate the gravity of the crisis.

Klasa prefaced his remarks about possible Soviet assistance by stressing that a recent visit to Moscow convinced him the Soviet Union would be extremely reluctant "to help us with military force to save socialism in Poland."

He also made these points:

The Polish Communist Party believes it is capable of solving the crisis without appealing for outside military assistance.

If there is a "real threat to socialism," Polish communists would have the right and duty to seek help from other socialist states. Such assistance, however, would not be requested "lightly."

He defined a threat to socialism as "a breakdown" in "the democratic process" -- in which case, the crisis would end in "tragedy and drama."

Poland's leaders are in almost daily contact with the Kremlin and other East European capitals on political and economic policies, but not on military developments.

Klasa noted that, apart from armed rebellion, it is possible to conceive of circumstances in which socialism is subjected to gradual erosion. In this case no military power would be of any use, he said, and instead the Communist Party would have to step up its political efforts to retain its power.

This appears to be the stage of political struggle in which Poland's rulers consider themselves at present.

It is accepted here that, if the party's authority disintegrates, military intervention by Poland's Warsaw Pact neighbors will follow.