Responding to international pressures, the government of Paraguay has agreed to an on scene investigation by the Inter-American Commission on Human Rights of conditions in the landlocked South American country.

Paraguay, under the rule of Gen. Alfredo Stroessner since 1954, has been accused frequently by groups monitoring human rights of permitting illegal detention, torture and death of political dissidents and Indians.

Last month, the New York-based International League for Human Rights found the rights situation there in "crisis."

The fourth coming investigation by the inter-America commission however, is considered important because the seven-member body is a dependency of the Organization of American States, of which Paraguay is a member. In effect, Stroessner has sanctioned a judgement by his peers.

Members of the commission are expected to begin their visit in the capital, Asuncion, early in March an official at the commission offices here said yesterday.

The U.S. government reflecting priorities of the Carter administration, has led efforts to expand the budget and activities of the rights commission. A mission currently is in El Salvador and another recently returned from Panama.

The United States took an active role in persuading Paraguay to receive the commission. The new U.S. ambassador there, Robert White, who previously served as deputy representative to the OAS, is a strong advocate of a wider role for the rights commission.

The International League for Human Rights report was a follow-up to its 1976 findings of massive rights violations.

Investigators Ben S. Stephansky, another former deputy representative to the OAS, and David M. Helfeld, former dean of the University of Puerto Rico Law School, again were allowed to visit the country. They found a sharp reduction in the number of political prisoners and improve conditions in the main jail.

Nevertheless, the investigators "found no compelling evidence of change either in the overall gravity of the human rights crisis or in the character of the basic institutions underlying that crisis."

Stroessner has ruled as a dictator over the 2.6 million Paraguaians on the basis that the backward country, torn by past wars and partitions, needs a strong executive.

Stephansky and Helfeld found that despite Stroessner's near absolute control, security police powers lead to many of the abuses.

Amnesty International, which won last year's Nobel Peace Prize found in another study that torture of prisoners is common in Paraguay.