Nicaragua's Sandinista leadership has written off the possibility of acquiring Soviet-made Mig warplanes in the near future, according to government officials.

The postponement of Sandinista ambitions to get Migs coincides with what one official said was advice from "friends" to seek "any other kind of plane except Migs" because the Reagan administration has focused on them its concern over arms obtained by the revolutionary government here.

It comes despite repeated declarations by Sandinista leaders that the United States is fomenting an attack on Nicaraguan territory by counterrevolutionary forces based in and supported by neighboring Honduras, which possesses Central America's most powerful air force. Defense Minister Humberto Ortega said last night that "warlike sectors" of the Reagan administration are issuing warnings about the Migs precisely as a way to justify the invasion plans.

"In this week, in these months, they say Nicaragua is to receive planes like Migs, planes like Mirages, a kind of Kfir plane, an Israeli plane, how do I know what type of plane?" Ortega asked in a news conference.

"We can say -- it is a reality -- that as for our Sandinista Army, at this moment, in this week, in these months that these gentlemen are talking about, really, the acquisition of this kind of technology is not in its plans, in its programs, in its requirements."

Questioned later, Ortega added: "This is not to say we are denying our right to arm ourselves . . . with adequate arms from any country."

Another Sandinista official, who requested anonymity, said that despite the refusal to foreswear Migs for good, the Nicaraguan government is convinced it will not obtain Migs or French-made Mirage warplanes for the foreseeable future.

The Reagan administration has charged the revolutionary Sandinista government that took power in July 1979 is preparing to get Mig 21 or Mig 17 fighter-bombers through Cuba or another Soviet ally. To back up the charges, administration officials have pointed to 70 Nicaraguan pilots and maintenance specialists being trained in Bulgaria and Cuba. This program has never been denied by the Sandinistas.

The U.S. government also has displayed intelligence photographs showing improvements on airfields at Puerto Cabezas and Bluefields, on the Atlantic coast, and Montelimar on the Pacific.

The reports from Washington depict the Sandinista leadership as a source of tension and instability in Central America, particularly in El Salvador where the United States is backing government efforts to put down leftist insurgents. Nicaraguan officials, while they show open sympathy for such rebel movements, insist the real source of tension is attacks on Nicaragua by U.S.-supported counterrevolutionaries repeatedly striking across the border from bases in Honduras.

"This is not a secret war, they U.S. officials say, but only internal 'harassment,' " commented Finance Minister Joaquin Cuadra in an interview. "So people accept it? Haven't they lost a little of their sense of morality?"

Cuadra said the first class of 30 Nicarguan pilots is due back next month from Bulgaria. But he said they will have no Migs to fly and, smiling, suggested they will join the unemployment roles.

"This goes to show that it is easier to get pilots than it is to get Migs," he added.

Young Nicaraguan pilots here in Managua were seen training on recently acquired light observation craft, landing beside a World War II T28 and a pair of Korean War-era T33 jets, all acquired by the previous Somoza government. The light planes were being outfitted with rocket-launching equipment.

Two French-built Alouette helicopters also sat on the tarmac, part of a $17 million deal last year that included air-to-ground rockets.

A trip this week to Puerto Cabezas in one of five almost antique C47s -- droning northward with four wicker baskets of chickens, three of milk and two of bread--brought a close look, just north of the seedy old port, at the landing strip that has been resurfaced with Cuban assistance and pinpointed by U.S. intelligence as a potential facility for the Migs.

William Ramirez, Puerto Cabezas' top civilian official, said the strip is now 1,600 meters (5,249 feet) long, which Army spokesman Roberto Sanchez said is too short to handle Migs. Since construction stopped for this phase last May, Ramirez added, "bad maintenance" has allowed development of several four-inch crevasses visible where the rough asphalt begins stretching at a 45-degree angle toward the nearby Atlantic Ocean.

Released U.S. intelligence photos labeled the strip as 6,015 feet long, about 800 feet longer than the distance cited by Ramirez, and U.S. sources argue that either length is able to accommodate Mig 17 or, with difficulty, Mig 21 warplanes.

Whatever the length, there was no evidence of support facilities necessary to use the strip for fighter planes. Such facilities are reported by the Reagan administration to be in place, however, at the Montelimar airstrip, built by the late dictator Anastasio Somoza at his home just south of Managua, and in the capital's Augusto C. Sandino International Airport.

This suggests a limited number of Migs, while they may not be available to the Sandinista government now, could be flown in if the Soviet Union, Cuba and Nicaragua itself were willing to take the political risk made clear by U.S. warnings, according to foreign analysts here.

In an interview last July, Ortega said he was interested in acquiring eight to 15 modern warplanes, preferably Mirages or Migs. Daniel Ortega, the defense minister's brother and head of the government junta, visited Paris recently, as did Carlos Nunez, one of the nine leaders of the ruling Sandinista National Liberation Front.

Knowledgeable sources here reported, however, that no official request has been lodged with the French government, although at least one informal approach has been attempted. These sources pointed out that not only does France appear unwilling to provide the weaponry, but also that Nicaragua is unable to pay for the costly craft even on easy terms.