BONN, West Germany (AP) _ Chancellor Helmut Kohl, trying to mend a rift in his government and ease international concern about German unification, today dropped his demand that Poland make concessions in exchange for a border treaty, officials said.

Kohl's government agreed to introduce a resolution in Parliament saying that a united Germany should sign a treaty promising it will never lay claim to Polish land, said the chancellor's chief of staff, Rudolf Seiters.

The proposed resolution, to be introduced Thursday, is the closest the West German government has come to assuring Poland that a united Germany would never seek to recover land lost after the 1945 defeat of the Third Reich.

Kohl has been reluctant to make such a statement, apparently fearing he would lose the conservative vote in December elections. He has said he cannot speak for a united Germany.

His recent statements on the border issue have stirred unease in Poland, the Soviet Union, the United States and elsewhere, just as the chancellor was seeking international support for German unification.

His statements also caused controversy at home. The opposition Social Democrats and Kohl's coalition partners, the Free Democrats, charged he was jeopardizing chances for unification.

Last Friday, Kohl heightened the dispute by demanding that any treaty recognizing Poland's borders be linked to Warsaw's waiving any war reparations and guaranteeing the rights of its German minority.

Those statements caused a crisis in the Bonn government. Foreign Minister Hans-Dietrich Genscher's Free Democrats agreed with Poland that Kohl must make clear guarantees to Poland.

Torsten Wolfgramm, a high-ranking official with the Free Democrats, confirmed today that Kohl had abandoned his demand that a border treaty be linked to any assurances from Poland.

''It is completely clear. A treaty would contain only the border question,'' Wolfgramm said.

Seiters said the resolution to be introduced in Parliament Thursday would call for a declaration by both Germanys on respecting Poland's western border. That would occur after East Germany's March 18 elections, he said.

According to Seiters, the twin parliamentary declarations should state: ''The Poles should know, that their right to live in secure borders will not now nor in the future be questioned by us Germans through land claims.''

Seiter said once Germany is united, its government would forge a treaty with Poland guaranteeing its current borders.

Earlier in Moscow, Soviet President Mikhail S. Gorbachev cautioned against any attempt by a united Germany to change the borders drawn at the end of World War II.

''Naturally, the inviolability of post-war borders is the main issue in this respect,'' he said.

Gorbachev's comments, made prior to a meeting with East German Premier Hans Modrow, were reported by the Tass news agency.