U.S. policy in Central America is "on the right track," Thomas R. Pickering told the Senate Foreign Relations Committee yesterday at his confirmation hearings as ambassador to El Salvador.

"On the other hand," Pickering said, "there are strong and polarized opinions in the United States on this issue, and they must be explained to the Salvadorans."

In his opening statement, Pickering, nominated to succeed Deane R. Hinton, said that "we all know that the problem of El Salvador cannot be confronted only by a military response. Democracy and development, dialogue and diplomacy, must be given a chance to work."

But he also said that "in the face of armed attacks in El Salvador and Central America, military protection and stability must be provided," that such assistance was "key to achieving social progress, political reform, respect for human rights and economic development in all sectors of the society."

Pickering, 51, was summoned to the United States from Nigeria, where he had been ambassador since 1981, to take on what he described at yesterday's hearings as "one of the most difficult ambassadorial posts."

He is to replace Hinton, who was recalled at the end of May in what the State Department said was the normal rotation of Foreign Service personnel but what administration sources have said is a move to consolidate control of the administration's Latin American policy.

Hinton was an outspoken ambassador. He gave a controversial speech in October, 1982, in which he scolded the Salvadoran government for what he called its poor human rights record and for failing to make brisker progress in curbing abuses. The administration publicly put some distance between itself and Hinton's words.

That outspokenness was the subject of a series of questions from Sen. Christopher J. Dodd (D-Conn.), who asked Pickering if he would have given such a speech.

Noting that Hinton gave a very similar speech later in his tenure that was not criticized by the administration, Pickering said: "I think both speeches contributed very much to important aspects of our policy in the area. I think they needed to be said."

"Of course we know," Dodd responded, "that the second talk was the farewell address" of Hinton.

Pickering said that the certification of progress in human rights, which has been required by Congress for continued military aid, "has helped us increase the concern in El Salvador about the situation there with respect to human rights abuses ."

"On the other hand," Pickering continued, "I think certification as now conceived has a number of problems"--including the arbitrariness of the six-month period for recertification and the possibility that leftist guerrillas schedule offensives in order to influence the certification process. He suggested a "more flexible system" that would "take into consideration the needs of the Salvadoran government."

He said that "on balance" the most recent certification was justified. The legislation under which certification was required has expired, and Congress is in the process of debating its extension.

The questioning by the four senators who attended the hearing at various times was gentle, and was often prefaced with praise for his record as ambassador to Jordan and Nigeria, and as assistant secretary of state for oceans and international environmental and scientific affairs.