Harry W. Shlaudeman, U.S. special envoy for Central America, met with Nicaraguan Ambassador Carlos Tunnerman here yesterday in the two nations' first senior-level contact since early this year when the United States suspended such exchanges with Nicaragua's leftist Sandinista government, but U.S. officials said later that there had been no narrowing of differences.

State Department spokesman Bernard Kalb said the meeting was "in lieu of a meeting that the United States had sought with the Nicaraguans" during the 40th anniversary celebration of the United Nations last week.

Kalb added that "the meeting reflects our wish to maintain regular diplomatic contact" and said Shlaudeman conveyed to Tunnerman "U.S. views on the importance of national reconciliation to a resolution of the conflict in Nicaragua."

The term "national reconciliation" refers to U.S. insistence that the Sandinistas reach an accommodation with Nicaraguan dissident forces, including the U.S.-supported counterrevolutionaries, or contras, fighting President Daniel Ortega's government.

Just before Ortega went to New York last week to address the U.N. General Assembly, his government cited the guerrilla threat and declared a state of emergency that set in motion a clampdown on civil liberties in Nicaragua. According to U.S. officials, Tunnerman showed no signs that Nicaragua might modify its position.

As a result, department officials cautioned that yesterday's session is unlikely to lead to resumption of the "Manzanillo talks," a series of meetings that had been conducted in Mexico by Shlaudeman and Nicaraguan Deputy Foreign Minister Victor Hugo Tinoco.

The United States stopped participating last January, saying Nicaragua was trying to use the forum to circumvent the Contadora process under which the Central American countries and neighboring Latin American states are seeking to negotiate a comprehensive regional peace.

Secretary of State George P. Shultz, accompanied by Shlaudeman, met with Ortega in Montevideo, Uruguay, in March, but they made no progress in resolving tensions.

The United States, seeking to test flexibility in Nicaraguan positions, sought a meeting during the U.N. anniversary session. However, the administration was unwilling to respond to Nicaraguan feelers for a meeting between President Reagan and Ortega.

A tentative U.S. proposal that Foreign Minister Miguel D'Escoto confer in New York with Shlaudeman and Elliott Abrams, assistant secretary for inter-American affairs, fell through because Abrams was abroad. As a result, U.S. officials said, yesterday's meeting was arranged as a substitute.