A Nicaraguan official said yesterday that a shipment of Libyan munitions halted by Brazilian authorities last weekend was intended for the Nicaraguan army and not leftist insurgents in El Salvador, a possibility suggested by some U.S. officials.

Raphael Solis, the first ambassador sent to Washington by the Sandinista regime three years ago, met with reporters on Captiol Hill as part of a lobbying campaign that the Nicaraguans have undertaken to counter Reagan administration charges that they are subverting their neighbors in Central America.

Solis, currently the secretary to the Nicaraguan Council of State, said that the refusal of the United States to enter into direct negotiations with Nicaragua and Honduras "could lead to war that could regionalize very easily."

State Department officials have said they have made repeated unsuccessful attempts to engage the Nicaraguans in negotiations. There was no immediate comment on Solis' remarks.

Solis said it should be no surprise that Nicaragua received arms from Libya and Soviet bloc countries, and that such arms supply relationships are openly disclosed in Managua. Asked why the Libyan pilots who landed in northern Brazil last weekend first identified their cargo as medical supplies, Solis said the Libyans would have to answer that.

Also yesterday, 65 members of Congress asked the chairman of the House Permanent Select Committee on Intelligence to "find a means of providing Congress and the country with a credible assurance that no U.S. assistance is being provided to any group engaged in military or paramilitary actions in Nicaragua."

The letter was circulated by Reps. Gerry E. Studds (D-Mass.) and George Miller (D-Calif.).