John Ferch, fired recently from his post as ambassador to Honduras, believes the Reagan administration is seeking a military solution in Nicaragua despite claiming publicly that it wants a negotiated settlement.

The 27-year Foreign Service veteran was dismissed last month after serving less than a year. Honduras is the staging ground for President Reagan's campaign to topple the Sandinista government in Nicaragua.

Days before Ferch's ouster, the House approved $100 million in aid for Nicaraguan rebels based in Honduras. Ferch said in an interview that if the administration does not pursue a negotiated settlement in Nicaragua, the $100 million will be just a "down payment."

The ex-ambassador said the time is ripe for diplomacy. He said his view "until the time they canned me was that you've got them the Sandinistas to the point where they've panicked so much they would negotiate some meaningful concessions."

If the administration fails to seize the moment and push for negotiations, he said, the $100 million "is going to go so fast, it's really just the first step. The logic of it all means that the next stage is an expanded military operation."

"I always thought we meant what we said. We wanted pressures so we could negotiate," Ferch said. "I'm beginning to think I accepted something that wasn't true." Ferch said the manner of his dismissal suggested that "our goal is something different. It's a military goal."

Ferch spoke by telephone from Canada, where he is vacationing.

Ferch previously served as head of the U.S. mission in Havana and deputy chief of mission in Mexico City. Administration officials said he had demonstrated excellent political skills in Honduras but blamed "significant" morale problems in the embassy on his management. He was also faulted for strained relations with the Honduran military and with the large Central Intelligence Agency station in Tegucigalpa. The State Department insists that policy differences had nothing to do with his firing.

In the interview, Ferch also said:Cuba and the Soviet Union are unlikely to interfere if the Sandinistas come under heavy military pressure. "I don't think they're going to fight down to the wire," he said. "The Cubans and Russians are not going to throw in troops like that. They are so concerned about a clash with us that they'll be very cautious." Honduras has a more comprehensive approach to Nicaragua than does the U.S. government. "They have been far better at negotiations than we have," he said. "When I would get instructions to go in and tell them things, I would follow them in my own way, because it was teaching them to suck eggs. They really were ahead of us always." The manner of his ouster undercut the newly elected civilian leadership in Honduras. He said U.S. officials "have let out the word that my relations with the military down in Honduras were not good. That is not true." Ferch said he always went first to President Jose Azcona rather than to the military. "I did that very consciously, and the military were understanding but not happy," he said. "They knew they were accepting a new role in life." But in saying that he did not get along with the military and suggesting that was a problem, Ferch said U.S. officials have "set alight a sleeping fire. It doesn't help Honduran democracy. There's no question about that. It's not me personally. The combination of getting rid of me and saying 'He didn't get along with the military' really does undercut the president."

Ferch said he believes he was fired "because they want somebody down there to be strong enough and proconsul enough that no Honduran government is going to object to anything. They're going to want someone to go in and say, 'Baby, this is the way it's going to be.' " He warned that if that was the intention, "nothing is going to happen" because Hondurans will not take orders.

The administration has not announced Ferch's successor, but officials said Everett Briggs, a career diplomat who was ambassador to Panama, is the leading candidate. Ferch called Briggs an excellent choice, but said, "What's ironic about this is that Ted isn't that type of diplomat. Ted really will support the civilian side of the house."

Ferch's view that a negotiated settlement is no longer the U.S. goal in Nicaragua is bound to be disputed by State Department officials, but his remarks underscored the current absence of any concerted diplomatic initiative.

Reagan named veteran diplomat Philip C. Habib as special negotiator in March, but despite several trips to the region, Habib has yet to visit Managua, Nicaragua's capital. Ferch said he was "extraordinarily impressed" by Habib during Habib's brief visits to Honduras. "Then, all of a sudden, he faded. You didn't hear from him," Ferch said.

Ferch said he had been convinced that military and psychological pressures by the United States would force the Sandinistas to the bargaining table to make meaningful concessions. "You know, the pressures are in place at two points: they are in place right now when you pass the vote by Congress for military aid to the rebels . Then the first time the rebels start shooting down helicopters," the military pressures against the Sandinistas are in place, he said.

Ferch said he had relayed to the State Department his assessment that the United States should take advantage of these pressures in negotiating. "But what can I tell you? I'm up here in the North Woods now. My overview has been discarded," he said.

Ferch said he was "fed up" with the Foreign Service because of anonymous criticism of him by former colleagues. After a sabbatical, he said, he will look for a job, but "I really don't think I want to have anything to do with the Foreign Service anymore."

Ferch and his family are building a cabin by a remote lake north of Lake Huron in southern Ontario.

"There is life after diplomacy," he said. "I am screwed but happy."