Poland's Communist leaders struggled today to get a firmer grip on their still uneasy country by making more top-level party changes and appealing to workers to return to their jobs.

The changes and appeals coincided with persistent labor unrest in the country and unconfirmed reports that new strikes are spreading in the key mining region of upper Silesia. Strikes and slowdowns known still to be under way included a wildcat walkout by transport workers in the Silesian capital of Katowice, an important southern industrial city.

In an apparent reponse to the agitation, two provincial party chiefs who were close associates of ousted party leader Edward Gierek have been removed from their posts.

The Polish press agency said last night that Zdzislaw Grudzien, a Politburo member and party secretary in Katowice, had asked to be removed from both positions during a party meeting attended by Poland's new Communist Party chief, Stanislaw Kania.

In addition, Jerry Zasada was relieved of his job as party secretary in Poznan.

There was no immediate official response in Poland to foreign reports that Soviet troops on maneuvers with Warsaw Pact forces in East Germany were moving in an area near the Polish border.

Both Grudzien and Zasada had been appointed local party chiefs in December 1970 when Gierek came to power. Their replacement was seen as a further move by Poland's new leadership to purge itself of the so-called "Silesian Mafia" -- a reference to those friends of Gierek who shared a power base in Poland's southern mining region.

The changes were also regarded as a sign of continued nervousness by party leaders, who appeared determined to get a firmer grip on key posts.

The government has issued a number of appeals for workers to return to their jobs to begin Poland's difficult recovery effort. Mieczyslaw Jagielski, the deputy premier who negotiated the precedent-setting agreement with shipyard workers last month in the Baltic port of Gdansk, appeared on television last night to ask Poles again to get back to work.

After him, Stefan Olszowski, the Politburo member in charge of economic planning and a former rival of Gierek's, was shown reaffirming that the spirit and letter of the Gdansk agreement would be kept but warning that if anyone wants to use them for "antisocialist aims," such action will be firmly resisted. Party authorities have frequently made reference to antisocialist forces said to be fanning the country's labor unrest.

Then in an attack clearly leveled at Gierek's economic policies, Olszowski went on to blame the recent labor troubles on the "arrogant actions" of the former leadership. Without mentioning Gierek by name, Olszowski said Poland's previous leadership had failed to present the real picture of the country's economic situation.

He said the rise in the cost of living and inflation that took place in the 1970s had been falsely treated as progress. The sources of Poland's current crisis, he said, were in the mistakes made in planning and economic management and in the lack of confidence in the truthfulness of government declarations.

Also appealing to workers to stop their protests, Olszowski listed some of the production losses already incurred by more than two months of labor troubles. Among them: 2.8 million tons of coal, 110,000 tons of steel, 73 million pairs of shoes, 14,000 washing machines.

In the second day of a strike by streetcar conductors in Katowice to back demands for higher pay, bus drivers joined the walkout in sympathy, sources said, after city officials did not show up for a bargaining session. The bus and streetcar drivers are members of the same transportation system.

A member of the joint committee of the transport system said his organization, which handles salary matters for transport workers in the area of Silesia, had not approved the strike.