Polish authorities proposed an amnesty for some political prisoners today as part of a legal package introduced in parliament that paves the way for the lifting of martial law expected Friday.

It pardons all women, persons under 21 years of age and those serving sentences of less than three years for martial-law offenses, politically motivated crimes or strike or protest actions. Those serving more than three years will have their sentences cut in half.

Dampening hopes that a more liberal political era might follow in Poland, the government of Gen. Wojciech Jaruzelski also introduced a "special regulations" bill that would extend for 2 1/2 years tough controls on labor, curtail academic freedoms, suspend features of Poland's economic reform and put off indefinitely the development of independent trade unions.

Deputy Justice Minister Tadeusz Skora, speaking about the proposed amnesty, told reporters tonight that of the 195 in prison for martial-law offenses, about 60 would remain locked up after the amnesty. He said another 460 are being held in detention pending trial, but he could not say how many of them would be freed under the amnesty bill.

A senior government official said, however, that the conditions of the amnesty exclude a number of hardcore Solidarity activists from being released--among them, seven top former union leaders and five leaders of the dissident Committee for Social Self-Defense (KOR) who face charges of antigovernment activity.

In an apparent concession to Poland's influential Roman Catholic Church, the Communist leadership delayed proposing a permanent tightening of the penal code, censorship law and regulations for conscription that was included initially in the government's draft of the "special regulations" bill.

Parliamentary sources reported that church officials had complained about using the omnibus bill to push through lasting amendments to diverse laws already on the books. One proposed change would have made participation in a banned organization--including Solidarity as well as disbanded student and professional organizations--punishable by up to three years in jail.

Archbishop Bronislaw Dabrowski, secretary of the Polish Catholic bishops' conference, reportedly met earlier this week with Stanislaw Gucwa, speaker of the parliament, to argue for dropping this and other proposed measures from the new bill. Some of the excluded measures may yet be voted into law as early as next week at another scheduled session of parliament, according to several deputies.

Still included in the bill, which is expected to be passed Thursday and to go into effect on the Polish national holiday Friday with the lifting of marital law, is a retraction of the right to establish multiple unions in Polish factories beginning in 1985. At the moment, only one union per factory is allowed, making the unions appear easily controllable by the government.

The proposed bill leaves the judgment as to when--and if--to allow union pluralism up to the Council of State in consultation with the existing, officially sanctioned unions.

In other action today, the parliament approved four constitutional amendments, including a provision for a possible "state of emergency" that could be invoked to counter a threat of internal security. Martial law, a "state of war" under current Polish law, initially was intended by the drafters of the 1952 constitution to answer external threats.

Embittered by the extended restrictions, Lech Walesa, the leader of the banned Solidarity union, has accused the authorities of further alienating the Polish people and creating conditions worse than martial law. Public resentment of the laws and the limited extent of the amnesty could encourage protest actions on the anniversaries in August of the strikes three years ago that led to Solidarity's founding.

A senior government aide said privately that the new regulations reflected a nervousness among top officials about managing the economy and controlling political opposition forces 19 months after the crushing of Solidarity. He said Poland still needs "several years of calm" to develop properly.

Officials are hoping that public disappointment with the proposed new measures will be offset by the abolition of martial law and the granting of at least a limited amnesty.

But the formal ending of martial law, which was imposed Dec. 13, 1981, is widely seen as having little real impact on everyday life. Authorities suspended military rule in December, ending most of its provisions then but leaving in place the political and administrative mechanisms. Other restrictions were made permanent by amendments to the penal code.

The amnesty, meanwhile, falls short of the blanket pardon for political crimes sought by the Catholic Church and critics of the government. It also contains provisions objectionable to the underground Solidarity leadership, whose members are invited to come out of hiding.

The proposed bill offers to pardon underground activists if they turn themselves in by the end of October and on the condition that they sign protocols confessing to criminal offenses done while in hiding. But the activists maintain that martial law itself, not their resistance actions, was illegal.

The amnesty also contains a provision effectively putting those released under it on probation. If caught before Dec. 31, 1985, committing an offense similar to that for which a person was jailed, the person will automatically have to serve the rest of the pardoned sentence or face resumption of the case that had been pending against him or her.

As for those currently detained but not yet convicted of political offenses, the bill calls for the freeing of anyone held on charges likely to bring jail sentences of less than three years. In "certain special circumstances," the chief prosecutor may also quash proceedings stemming from charges that carry a longer punishment.

The Reagan administration has told Poland that some of the economic sanctions imposed when martial law was declared and Solidarity banned would be rolled back if a substantial number of prisoners were released with the lifting of martial law.