Poland's Communist authorities today disclosed details of special emergency powers that will enable them to keep a tight rein on social unrest following suspension of major restrictions of martial law at the end of this year.

The disclosure followed yesterday's televised speech by the country's military leader, Gen. Wojciech Jaruzelski, in which he announced that "the main rigors" of martial law will be lifted and that many political internees will be freed soon.

At a meeting of the Sejm, the national legislature, on the first anniversary of the imposition of martial law, the Polish head of state, Henryk Jablonski, said that the country was still threatened by an underground opposition and by "external enemies." He presented two draft bills that he said were designed to protect the state and its citizens during a transitional period until the full lifting of martial law.

The new legislation authorizes the Council of State, the collective state presidency of which Jablonski is chairman, to suspend or reintroduce any of the martial-law provisions at very short notice. It also institutionalizes what amounts to a state of emergency under the name of "the period of the suspension of martial law."

During this period, the remaining 200 political internees will be released. In some factories, military-style discipline will be somewhat relaxed and the scope of military courts reduced. Travel restrictions within Poland are to be lifted and some rights of assembly and protest restored, subject to strict limits.

Some independent associations may be allowed to operate again within the next six months, but not the Solidarity trade union, which was legally disbanded in October. Jablonski said a conditional amnesty would be considered on a case-by-case basis for the estimated 3,000 Solidarity activists convicted of illegal union activity and other crimes under martial law.

A close reading of the new laws, which the Sejm is expected to pass formally on Saturday, makes clear that the authoritarian style of government associated with martial law is likely to continue for the foreseeable future. None of the conditions for social peace outlined in a letter to Jaruzelski by the former Solidarity leader, Lech Walesa, have been fully met as a result of the government's actions.

One clause in the new law states that any worker who takes part in a strike or demonstration "contrary to existing rules" or "causes disturbances at their place of work" can be dismissed on the spot. Students are subject to similar penalties for "disturbing the peace."

This provision was criticized in a speech by an independent Catholic member of the Sejm, Janusz Zablocki, who said it allowed "all kinds of interpretations." Zablocki also criticized the growth of arbitrary bureaucratic power over the past year and said this had contributed to the alienation of ordinary people from the government.

Zablocki, whose views reflect those of the Roman Catholic hierarchy, welcomed the legislation as "a positive step" but said many citizens had expected a total lifting of martial law, which would have had "a much greater psychological effect."

[Two exiled Solidarity leaders, Henrik Stodolny and Wojciech Rudnicki, said in Stockholm that the union underground would continue "slowly gnawing away at the establishment . . . to teach Poles how to maintain resistance," The Associated Press reported.]

At a press conference today, government spokesman Jerzy Urban said it was hoped that the remaining Solidarity internees would be released in time to spend Christmas with their families.

The government has claimed that Poland's economic position has improved significantly as a result of martial law, particularly in the vital coal industry where miners now work six days a week. Lines outside stores have been cut, but this is due more to large price rises than to any increase in the supply of goods.

Asked about reports that Walesa planned to address a meeting in Gdansk on Thursday, the 12th anniversary of the bloody suppression of food riots along the Baltic Coast, Urban said that no request for permission to hold a demonstration on that day had yet been filed with the Interior Ministry. If a demonstration went ahead, he warned, it would be illegal and would be broken up by the police "no matter what sorts of names are connected with it."

In his speech to the Sejm, Jablonski said some continuing restrictions were necessary for economic reasons. Workers subjected to military discipline during the period of martial law still will not be able to leave their jobs without permission, and managers may extend compulsory working time to 46 hours a week.

The new legislation also provides that people accumulating underground leaflets or other illegal publications at home could be liable to prison sentences of six months to five years. Anyone undertaking "activity aimed at disturbing the public peace" can be sentenced to up to three years' imprisonment.

The government also will retain the right to censor correspondence or tap telephone conversations on the order of the prosecutor general.

No Polish leader has yet said officially when martial law is likely to be lifted, other than saying that this will happen in "as short a time as possible".

Strict controls over the press will be maintained through the transitional period. A liberal censorship law passed during the Solidarity era will remain in suspension, Urban confirmed today.

Jablonski said today that to benefit under the proposed amnesty, prisoners convicted under martial law will have to "express regret" for their activities in the past. Family considerations will also be taken into account, as well as behavior in prison.