Poland is holding up approval of a new American ambassador until the Reagan administration makes "a sort of positive gesture" toward Warsaw, a senior Polish official said today.

The official said that the nominee--John D. Scanlan, a career foreign service officer--had been proposed more than three months ago by Washington. Ambassador Francis Meehan, whom Scanlan was to replace, left Warsaw in February, and the embassy currently is under a lower ranking diplomat.

The State Department declined to comment. A U.S. official said Scanlan, who has served three times in Poland, is now at the Fletcher School of Law and Diplomacy, in Medford, Mass.

The Polish Foreign Ministry official, who spoke on condition he not be named, indicated that Poland intended to take some steps toward further national reconciliation before Pope John Paul II's arrival for a visit to his native land on June 16. He asserted, however, that it was up to the United States to make the first moves toward breaking the ice in U.S.-Polish relations.

"Certainly the visit may play an important role in East-West relations, in improving the psychological climate," he said.

Poland's Communist authorities have been reluctant to appear to be making concessions under pressure from the church or western states. But the ministry official stated that the papal trip, although ostensibly a religious pilgrimage, would have a domestic political impact.

The official said Poland would not lift repressive measures left over from the period of formal martial law before the pope's visit, nor would it meet calls by the Roman Catholic Church for a general amnesty for political prisoners. But he added that "there will be a lot of improvements" in the country's internal situation before the pope's arrival.

Relations between Poland and the West went from bad to worse following the declaration of martial law in December of 1981 and the imposition of western economic sanctions. Martial law officially was suspended in December, but many of its restrictions remain in effect.

The Reagan administration has suspended agricultural credits to Poland, barred Polish fishermen from U.S. waters and revoked landing rights in the United States for Lot, Poland's national airline. Washington has also blocked negotiations on rescheduling Poland's official foreign debt and on Poland's joining the International Monetary Fund.

After the formal abolition of the independent trade union Solidarity last October by the Polish parliament, the United States also withdrew Poland's most-favored-nation trading status, effectively raising the prices of Polish imports. The European Community, meanwhile, has halted food sales to Poland at the preferential prices formerly offered.

Senior officials in the West German government of Chancellor Helmut Kohl are known to favor a softening of the coordinated western stand toward Poland. France continues to take a hard-line position on Poland.

While Poland's relations with West European states have been disturbed by the sanctions, the Warsaw government has singled out the Reagan administration as the main instigator of the East-West confrontation, and insists the United States make the first move toward an easing of relations.

"Much doesn't depend on us but on the American side," the ministry official said. "Certain movement should start there. But we have been telling them that we will be responsive" to U.S. gestures.

He confirmed that a Polish Foreign Ministry department chief, Jan Kinast, visited Washington in early February for exploratory talks with the Reagan administration and was led to believe that a reevaluation of U.S. policy was under way and would produce something in "two or three weeks."

Asked what had been expected, he replied: "A gesture, an opening of the process that would lead to better relations"--such as restoration of landing rights for Polish charter flights or a "change in U.S. propaganda" about Poland.

A U.S. diplomat said Kinast had met with Undersecretary of State Lawrence S. Eagleburger, among others, for "general discussions" on U.S.-Polish relations but stated that "no commitments were made."

"We are waiting for a sort of positive gesture on your side," the Polish official said, adding, however, that he did not mean to make a "formal linkage" between such a gesture and approval of Scanlan.

Touching on a number of East-West issues, the official also said it is "likely" that Poland and the Vatican will agree to open formal diplomatic relations, or something close to that, around the time of the papal visit.

There has been much speculation that the papal pilgrimage would serve as an important political pivot for the government of Gen. Wojciech Jaruzelski to ease repressive measures and for western governments to back off from economic sanctions.

While ruling out a general amnesty for the approximately 1,500 persons convicted of martial-law crimes, the official said the process of considering clemency on a case-by-case basis for political prisoners might be accelerated. An official report in late March said the Council of State had granted clemency to 244 persons.

On the question of restoring a dialogue between government and society, the ministry official said simply that "there will be progress" at the first national congress in May of the Patriotic Movement for National Rebirth, the citizens' action committee sanctioned by the authorities as the primary new funnel for social initiatives.

The official did not elaborate on other moves the government is considering before the seven-day papal visit starts June 16. What he did outline, though, appeared to fall short of the Reagan administration's conditions for an end to the sanctions--namely, a complete lifting of martial-law measures and the restoration of a dialogue between the authorities and "truly representative forces of the Polish nation" such as the dominant Catholic Church and free trade union groups.