Polish leader Stanislaw Kania accused his predecessor, Edward Gierek, of "arrogance of power" today in a speech that blamed individuals rather than the ruling Communist Party for the current crisis in Poland.

Addressing the party's Central Committee assembly, Kania called for changes in the way Poland is run, including greater economic decentralization, but he insisted that there would be no fundamental change in the structure of the one-party state or its alliance with the Soviet Union.

Meanwhile, a spokeswoman for the dissident Workers' Defense Committee (KOR), quoting independent union sources in Gdansk, said that six Soviet naval vessels had arrived in Gdansk harbor at noon yesterday at the start of a one-hour nationwide strike. The claim could not be independently confirmed, and officials said "goodwill visits" by Soviet ships are a regular occurrence.

The vessels, which are now reported to have left, were said to include a rocket-carrying cruiser, two ships carrying rocket launchers, a gunboat, a troop carrier and a surveillance ship that can be used for jamming communications.

The KOR spokeswoman, Eva Kulik, described the force as "a show of strength apparently designed to coincide with the strike" called by the new union to protest alleged delays in implementing agreements with workers along the Baltic coast last month. But she added: "We're not upset."

Kania's criticism of Gierek was the sharpest public attack on the former Communist leader since his resignation a month ago. Kania also criticized a former prime minister, Piotr Jaroszewicz, who was fired last February as a scapegoat for economic failures.

Saying the previous government was characterized by "arrogance," Kania charged that Gierek and Jaroszewicz had taken an aggressive attitude to criticism and relied too much on opinions originating from inside the ruling circle. "In their hands, big power, too big power was concentrated."

Kania was himself a close associate of Gierek. As a member of the ruling Politburo since 1975, he was given responsibility for the Army and security services. But he has now apparently decided on the need for a break with the past.

While the Central Committee meeting was being held behind closed doors, Kania's 90-minute speech was broadcast in full on radio and television after the evening news.

The unusual publicity given to the speech, at a time when the Plenum is still in session, suggested that Kania was keen to get his views across to the nation above the heads of the Central Committee. Composition of the 143-man policy-making body is believed to be weighted in favor of the hardline element in the Polish Communist Party.

Among the organizational changes proposed by Kania were additions to the party statutes that would restrict the powers of the Politburo and the party's first secretary. He said that the powers of the Sejm, the Polish parliament, should be strengthened together with that of the Supreme Control Commission at present headed by the controversial former security chief, Mieczyslaw Moczar.

The nationalistically inclined Moczar, who appears to have regained some of the influence he lost in the early 1970s under Gierek, was one of the first speakers in the debate which followed Kania's address. Another speaker was Jerzy Lukaszewicz, who was dropped from the Politburo in August in apparent disgrace and has the reputation of being a hardliner.

The debate apparently involved the first major clash between reformers and hardliners on the Central Committee over the causes of the present crisis. The plenum had to be postponed for at least a week because of divisions within the leadership.

Many senior party officials, both in Warsaw and the provinces, are understood to have voiced strong opposition in advance to any major shakeup of the party apparatus. Despite the dismissal of six members of the 14-man Politburo, the upper reaches of the Polsih establishment have remained more or less intact.

The reformers, on the other hand, believe that unless blame is apportioned for the crisis, Poland faces the threat of the strikes recurring in the future. They have urged the convening of an early emergency party congress at which fresh elections to the Central Committee would be held.

Kania appeared to tread a careful line between these two factions. He said it was necessary to ensure that the deformations and mistakes of the past decade were never repeated. But he also attacked what he called "enemies of socialism" -- an apparent reference to dissident groups -- who he said were intent on overthrowing the system.

Condemning widespread corruption in public life, he promised an investigation into all private homes built over the last 10 years. Some Communist officials have been accused of using public money to build themselves luxurious villas.

Kania also strongly criticized yesterday's strike called by the Solidarnosc (Solidarity) union. He described it as "irresponsible" and said it would only aggravate Poland's extremely serious economic position.