Public criminal trials of Polish government and Communist Party officials accused of corruption and abuse of power will begin within the next two months, a Polish party spokesman said today.

Without naming those to face trial, Jozef Klasa, spokesman for the Central Committee, told reporters the proceedings would be timed to precede the special Communist Party Congress set for July 14-18 -- a move presumably intended to dramatize the party leadership's stated commitment to the process of self-renewal and reform.

Important indications of this commitment are the decisions to set up a special commission to investigate abuses by former and current party leaders and to double the number of worker and student delegates at the coming special congress.

Public anger at abuses of power and privilege by Communist officials was a major factor in the disillusionment here that has fed the pressure for change. In the atmosphere of easy money and lavish living which seemed to have flourished under the deposed party leader Edward Gierek, a number of party and government officials are believed to have stepped well over the line of privilege into corrupt practices amassing fortunes, expensive villas, fast cars and other luxury items.

So far, though, relatively few scandals have been detailed in public.The best known is the case of Maciej Szczepanski, former head of Polish radio and television, whose list of extravagances enlivened gossip here for weeks following announcement last September that he was under investigation.

More recently came the disclosure that a former prime minister, Piotr Jaroszewicz, was also under investigation for enriching himself during 10 years in office.

Gierek himself who has faced a groundswell of resentment for the failures of the past decade since he was ousted in disgrace last September, has also been reported by the Polish press to be facing formal inquiry.

It was presumably in response to demands by party officials for action against Gierek that the Central Committee last week set up a special commission to investigate the guilt of former leaders for the current economic situation in Poland.

Klasa today said this commission, which will judge political irresponsibility separate from criminality, is expected to complete its work before the July congress. He said the commission would investigate both those who have left official positions and those "still in exposed jobs."

Asked whether Gierek, who has not been seen in public since his ouster, would be called before the commission, Klasa said, "It would be strange to me if they didn't talk to him."

As if to give a sense of balance to the current cleaning effort, Klasa also said the trial of Leszek Moczulski, a right-wing dissident, should begin as soon as possible. This would help to "clear the air" before the party congress, Klasa said.

The congress is being anxiously anticipated for the formal stamp it is expected to place on democratic reforms within the formerly ossified party system.

Polish party leader Stanislaw Kania has strongly endorsed the spirit of change in the face of a growing grassroots movement pressing for an overhaul of the party leadership and statutes.

Klasa stressed that the party leadership already has demonstrated its commitment to change, noting the alterations in party statutes proposed by the Central Committee last week. He also called attention to the precedent-setting election of two party rank-and-file members into the ruling Politburo.

"Those who don't live inside the party don't realize what weight this carried," the senior spokesman said. "It is clear the party is getting up off its knees and becoming a leading force again."

At the same time Klasa disputed those critics of the reform process who have charged that the party is drifting away from Lenin-style socialism toward a Polish brand of social democracy.

Elaborating on the changes in party election procedures for the upcoming congress, Klasa said there would be at least a doubling of the number of delegates directly elected from worker and university groups. But he did not say what percentage of the total number of delegates attending the congress this would represent.