President Reagan, citing expectations that martial law will be eased in Poland, said yesterday that if the Polish military regime takes "genuine liberalizing actions" he will respond with "equally significant and concrete" steps to relax the U.S. sanctions against Poland.

"The United States can only respond to deeds, however, and not to words," Reagan stressed at a White House ceremony where he signed two proclamations calling on Americans to show continued solidarity with the Polish people.

"We're not interested in token or meaningless acts that do nothing to fundamentally change the situation in Poland today -- or to replace one form of repression with another," the president said in reference to anticipation that Poland's military ruler, Gen. Wojciech Jaruzelski, will suspend martial law on Monday, the first anniversary of its imposition.

However, the administration does not believe that Polish authorities intend to go beyond a symbolic gesture and allow any return to the liberalization and pressure for reform that led to the military crackdown last year.

For that reason, U.S. officials said privately, Reagan's remarks were intended to put the Warsaw regime on notice that the United States is prepared to make "step-by-step" responses geared to specific actions that mark a genuine easing of repression.

The president reiterated the three conditions outlined by the United States last year and adopted by NATO at a January meeting of alliance foreign ministers. They call for an end to martial law; the release of Lech Walesa, leader of the banned independent trade union, Solidarity, and other political prisoners; and the resumption of dia-logue among the Polish government, the labor movement and the Roman Catholic Church.

"Our three conditions stand, come hell or high water, and the Polish authorities have to be in no doubt about that," said a senior administration official, who asked not to be identified.

He noted that, while the recent release of Walesa and other prisoners are steps in the right direction, the United States remains wary that Poland's rulers may end martial law only to replace it with some form of emergency rule or more subtle forms of repression.

The Jaruzelski government, hard-pressed financially and isolated from the West, has been seeking a rollback of the sanctions imposed by the United States and other NATO countries. But, the U.S. officials insisted, the United States is willing only to consider each liberalizing step on its merits and, if it is regarded as easing the internal Polish situation, to make an equivalent gesture in hopes it will encourage further progress.

That was the tack taken by Reagan yesterday as he stood between two untrimmed Christmas trees in the White House East Room with members of Congress and representatives of Polish-American groups to release the two proclamations: one marking the beginning of Human Rights Week and the other designating Monday as a "day of prayer for Poland."

"In introducing sanctions against Poland last December, I noted that these sanctions were reversible, and this remains the case," Reagan said. "I will stress today the United States is prepared to respond to genuine liberalizing actions by the Polish government. Any such actions will be the subject of careful discussions with our allies. I repeat, if the Polish government introduces meaningful liberalizing measures, we will take equally significant and concrete actions of our own."

In one obvious easing of the U.S. stance, Reagan made no mention in his remarks of Solidarity. Instead, he spoke in vaguer terms of "the beginning of dialogue with truly representative forces of the Polish nation . . . . "

The senior official acknowledged that this represented U.S. recognition of the "reality" that Solidarity has been significantly weakened. But, he added, the United States has not retreated from the position that the Polish government, and its Soviet backers, "must come to grips with the reality that it must find a way of dealing with Polish labor, whether you call it Solidarity or another name."

U.S. sanctions include suspension of agricultural credits, restrictions on Polish diplomats, and bans on Polish fishermen operating in U.S. waters and on LOT, Poland's national airline, flying to this country. The United States also has withdrawn most-favored-nation tariff status from Poland and blocked its bids to reschedule its foreign debt and join the International Monetary Fund.

Some West European governments have advocated taking a more flexible line, and the senior official acknowledged that suspension of martial law is likely to increase the pressure. In particular, he said, the European allies probably will call for movement on the debt-rescheduling problem and for greater western dialogue with the Jaruzelski regime.