Poland's Communist Party leader Edward Gierek today tried to defuse a fast-spreading general strike along this country's important Baltic coast by hinting at a possible shakeup in the leadership and some improvements in standards of living for workers. But he flatly rejected worker demands for sweeping political reforms.

"Poland can be an independent state only under socialism," Gierek said in a nationally televised speech. "There are certain limits beyond which we cannot go."

The Polish leader, who cut short a vacation in the Soviet Union to return here Saturday and has postponed a state visit this week to West Germany, added: "It is our duty to state that no activity that strikes at the political order of Poland can be tolerated. On this fundamental problem, no compromise is possible."

Although he made no direct reference to the Soviet Union, Gierek appeared to be reminding his people about Soviet armed interventions in East Germany in 1953, in Hungary in 1956 and in Czechoslovakia in 1968 to put down similar popular unrest.

Later, the leader of the dissident Self-Defense Committee, Jacek Kuron, told Western journalists that his organization had received reliable reports that Polish security forces had been reinforced near the strike-bound city of Gdansk.

Gierek's 30-minute speech appealed for national unity and an end to the wave of labor unrest that has brought many Polish factories to a standstill over the last seven weeks. But his address was couched in the standard communist rhetoric, and he showed no sign of being willing to make a major compromise to help resolve the crisis.

More than a hundred factories and other facilities are now thought to be affected by the strikes, centered on the giant shipyards on the Baltic coast where more than 50,000 workers have walked out. Shipping from Poland's Baltic ports is also at a virtual standstill.

Meanwhile, reports were circulating here of unrest in Poland's industrial heartland of Silesia, center of the country's important coal mining industry. If the reports, which are still unconfirmed, are true, it could spell disaster for Gierek personally, since it is to the miners of Silesia that he owes his chief political support and strength.

In his first address to the nation since labor unrest first broke out, Gierek condemned "anarchist and anti-socialist groups" which, he said, were trying to exploit the strikes for their own ends. This, he warned, would not be tolerated.

Rejecting out of hand calls by strikers for political reforms such as an end to censorship and the establishment of independent trade unions, the Polish leader said: "Nobody can count on compromise and surrender in the face of political demands."

His television appearance, an almost unprecedented event for a communist leader, came shortly after the cancellation of an important trip he was to have made to West Germany Tuesday to seek help in overcoming Poland's serous economic problems and particularly its indebtedness to the West. The polish debt is now estimated to be in the region of $23 billion dollars.

Meanwhile, the official Communist Party newspaper Trybuna Ludu alluded to the possibility of some form of Soviet intervention here for the first time. In a long commentary, it warned that the strikes could put Poland's security in danger.

Gierek, who owes his own rise to power to similar strikes in the Gdansk region 10 years ago, revealed there would be a meeting of the policy-making Politburo of the Communist Party in the near future. In what was seen as references to a posible personnel shakeup, he criticized the bureaucratism of the trade union movement, and said it would even be possible to discuss who was responsible for Poland's present crisis.

But he emphasized that bargains must be kept by both sides. This was interpreted as a veiled attack on strikers at the giant Lenin Shipyard in gdansk who rejected a tentative agreement with management to return to work last Saturday. The workers decided instead to continue the occupation of the yard in solidarity with other striking plants along the coast.

In Gdansk itself, negotiations between management and workers have broken down in most cases following the decision to set up an integrated strike committee representing all the workers. Polish Deputy Prime Minister Tadeusz Pyka has been appointed head of a govrnment commission to investigate the workers' grievances.

The strikes are reported to have spread westward along the coast to the city of Szczecin near the East German border.

Gierek said he could understand the discontent of Polish workers with shortages, long lines outside shops and rising prices. He promised gradual salary increases, improved meat supplies and the consideration of economic reforms.

But the general tone of his speech differed little from that of Prime Minister Edvard Babiuch Friday. It was greeted with cries of derision from the striking workers.

Washington Post correspondent Bradley Graham reported from Bonn:

West German Chancellor Helmut Schmidt and other German officials, still preparing for Gierek's visit this morning, had been hoping to hear from the Polish leader firsthand about the unrest under way in his country.

Also high on the agenda of the two leaders' talks was the state of East-West detente and the chance of some kind of disarmament conference growing out of the Conference on Security and Cooperation in Europe meeting to review the Helsinki accords in Madrid this November.

On the issue of bilateral economic relations, a consortium of 25 West German banks announced last week it had put together a credit package of $690 million dollars to help keep the Polish economy afloat for another year.