Polish authorities today unexpectedly postponed an important session of Poland's parliament amid unconfirmed reports that Soviet Bloc leaders will meet shortly to discuss a coordinated policy on the crisis in Poland.

The official explanation given for the postponement is "the temporary indisposition" of Premier Wojciech Jaruzelski. Government spokesmen refused to elaborate, other than saying that the parliament session, originally scheduled for Monday, will be held Friday.

The Soviet government newspaper Izvestia said tonight that counterrevolution in Poland had raised itself to its full height and that "many people today are asking with extreme fearfulness: what next?" Reuter reported from Moscow. It quoted Izvestia as saying that the past seven "dramatic" months had brought Poland to the brink of economic chaos and that the activites of antisocialist forces "placed a question mark over the fate of socialism in Poland."

[Izvestia asserted that "creeping" counterrevolution was growing more brazen and implicitly criticized Polish authorities for failing to check it.]

Jaruzelski's address to parliament had been eagerly awaited as the first authoritative statement of government policy since its last-minute agreement with the independent trade union federation Solidarity that averted a general strike Tuesday.

The premier has not been seen in public for two days and is known to have canceled some appointments. Observers say it is conceivable that he is suffering from illness or overwork. But another explanation heard is that the Polish leadership is awaiting the outcome of developments elsewhere in Eastern Europe.

Despite heightened concern in the West about a possible Soviet intervention in Poland, there is no visible evidence here of increased security precautions. Most Poles took advantage of bright spring sunshine today to enjoy one of the "free Saturdays" conceded by the government after a test of strength with Solidarity in January.

Meanwhile, reports circulated in East European capitals that a high-level meeting on Poland will take place at or shortly after the Czechoslovak Communist Party congress, which opens in Prague Monday. Some Western diplomats think Soviet President Leonid Brezhnev might attend the congress, providing an ideal opportunity for another Soviet Bloc summit meeting.

The last summit devoted to Poland took place in Moscow in December when the Polish leaders won a qualified expression of confidence in their ability to control events here. But they also explicitly recognized as legitimate the interest of other communist countries in Poland's problems.

A meeting between Soviet and Polish leaders was held after the Soviet party congress in Moscow at the end of February. Then the tone of the final communique was much more critical with references to the need to "turn the course of events."

This ambiguous phrase was given different interpretations. Polish officials understood it in the sense of restoring calm and order, while the Kremlin appears to have envisaged steps to reassert party control over Solidarity. If so, it is clear that its expectations have not been met.

What has happened, however, as a result of the crisis over alleged police brutality against Solidarity members in Bydgoszcz is that the moderates in both camps in Poland have been strengthened. Solidarity leader Lech Walesa last week fended off criticism of the settlement with the government by producing a sheaf of messages of support from factories and plants around the country.

He accused the militants in Solidarity's national leadership of being out of touch with grass-roots feeling, using much the same phrase as workers who spoke up in criticism of the Communist Party leadership at the Central Committee meeting.

Solidarity's national committee eventually endorsed Walesa's position by voting to end a general strike alert throughout the country and disciplining several hard-line members. This gesture marked the first time that Solidarity had moved against any of its own supporters.

The Polish Central Committee, on the other hand, shrunk from dismissing hard-liners from the Politburo as demanded by reform-minded, rank-and-file Communists. In the dramatic circumstances, it was clearly important to maintain at least a facade of unity in order to ease the concern of Poland's Soviet Bloc neighbors.

The meeting did instruct Politburo members to meet with local party branches as soon as possible. One of the first to do so has been Stefan Olszowski, the propaganda chief who is widely identified with the conservative wing of the leadership.

Among the questions put to him by miners in Silesia, as reported in the Polish press, were: "Why is it necessary for us to get our information about events in Poland, and in the Communist Party, from Western radio stations like Radio Free Europe?"

The tension has eased noticeably in Poland during the last week since the strike settlement. The sense of relief, mingled with exhaustion, is so great that few ordinary Poles seem to give much serious thought to the possibility of a Soviet intervention.

During the tense period that led up to the general strike, however, Solidarity leaders made contingency plans for various possible outcomes to the crisis, including outside intervention. Some of these contingency plans are now circulating in internal Solidarity bulletins.