Millions of Polish workers defied the government today by refusing to go to work in the second nationwide boycott this month to press for a five-day work week.

The free trade union federation Solidarity, which called for the mass boycott, reported idle factories, shipyards and offices throughout Poland but said that public transportation and other essential services were running at the normal level for a free Saturday.

In an apparent attack on Solidarity's leadership, the Communist Party newspaper Trybuna Ludu today raised charges of "moral terror and political skulduggery" but stopped short of blanket condemnations of Solidarity.

A more direct attack on the union leadership came from the Soviet news agency Tass, which said union actions were leading to "deliberate confrontation with organs of the people's power" and were an attempt to disrupt Poland's economic and public life.

Union officials said the response to the boycott call among about 10 million Solidarity members was overwhelming, especially in major industrial centers. There were no immediate government estimates.

When Solidarity mounted a boycott on the first working Saturday of the month, Jan. 10, the government said 60 percent of the labor force ignored union instructions. The union said the majority of workers stayed at home.

Today's boycott followed two days of warning strikes across Poland that yesterday grounded all domestic air traffic for the first time in memory, kept Warsaw's largest daily newspaper off the stands and even affected the official government new agency.

The state radio carried reports of large-scale absenteeism. It said only 10 percent of the labor force turned up for work in the Gdansk shipyards, that attendance in many enterprises in Warsaw was no higher than 20 percent and that most factories in Lublin were closed. In two agricultural machinery plants in Koszalin, 74 of 1,000 and 6 of 300 workers showed up.

A Reuter correspondent checking five major plants in Warsaw said factory guards had reported that only a fraction of the work force went to work. A guard at a car factory said 2,000 people normally passed through his gate, but only about a dozen had turned up today. It was the same at a radio factory where a huge banner read "Solidarity Wants Justice and Democracy in Poland."

In many cases, the small groups of workers who arrived were sent home. Only managers and foremen remained inside the factories, which were festooned with the red and white Polish flag, now the symbol of labor protest in Poland.

Solidarity, which demands a five-day, 40-hour week, has stated before today's boycott that it was ready to compromise on the issue. Agreements signed with strikers last summer provided for the introduction of a 40-hour work week but set no timetable for its implementation.

Shortly before the new year, the government announced it would phase in the 40-hour week over a five-year period and ordered Poles to work on two Saturdays a month. The union responded in anger, saying it had not been properly consulted, and four rounds of negotiations failed to resolve the dispute.

The failure of negotiations pointed to a hardening of attitudes on both sides, and underlined the views of both the government and the unions that the dispute was no longer just about free Saturdays.

Solidarity says the question of Saturdays is merely symptomatic of the way the government is trying to back out of promises made last summer.

The union says if it yields on the Saturday work issue it will also lose out on other promises, such as relaxation of censorship and the freeing of political detainees.

Solidarity also argues that it has been unfairly portrayed in the official media as a wrecker of the economy. It says that, if the government concedes the free Saturday issue in principle, it will call on its members to work voluntarily on some Saturdays to make up production losses.