MANAGUA, NICARAGUA, AUG. 11 -- President Daniel Ortega today publicly opened a process of complying with a Central American peace accord signed last week, but opposition politicians expressed skepticism that required democratic changes would be carried out.

Ortega met Cardinal Miguel Obando y Bravo, the leader of Nicaragua's Roman Catholic Church, and representatives of 11 opposition political parties to discuss opposition participation in a National Reconciliation Commission. It is to be established within 20 days under a provision of the peace agreement signed Friday in Guatemala City by Ortega and the presidents of El Salvador, Honduras, Costa Rica and Guatemala.

Under the agreement, each government is required to choose a four-member commission consisting of a government representative, a person nominated by the conference of bishops, a nominee of the internal political opposition and a neutral person.

The peace agreement calls for cease-fires in Central America's wars, amnesties, an end to aid for rebels and internal "democratization" within 90 days of signing.

Ortega, wearing a black jacket over a green military uniform, handed copies of the peace agreement and an invitation to Obando y Bravo during the ceremony at a country club and said this showed the government's commitment to the accord.

The president and the cardinal, who is strong critic of the Sandinista government, said afterward they had agreed to discuss reopening of Radio Catolica, the radio station closed by the government last year. Asked about the prospect of reopening the opposition newspaper La Prensa, Ortega said, "We'll have to see about it."

Ortega also presented copies of the peace plan and invitations to representatives of 11 legally registered opposition political parties to the left and right of the ruling Sandinista National Liberation Front. The parties are to nominate candidates for the reconciliation commission, and the government is to choose one member and an alternate from among them.

Foreign Minister Miguel d'Escoto said Obando y Bravo had been invited to nominate three bishops for the commission. "This is an indication of the seriousness with which we take our commitment to total fulfillment of all the agreements in the accord signed in Guatemala," he said. "We're going to prove that the Nicaraguan revolution is very much committed to democracy." He said Nicaragua was the first country to start the processes required by the peace agreement.

Opposition leaders said after the ceremony, however, that the event was a public relations exercise and that more was needed to show the government's good faith.

"It was a publicity show more than anything," said Eric Ramirez of the Social Christian Party. He said that until the Sandinistas lifted a state of emergency, freed political prisoners and allowed closed newspapers and radio stations to reopen, the opposition would not take "democratization" seriously.

Virgilio Godoy, the president of the Independent Liberal Party, said the ceremony was "for export" and a "bureaucratic procedure."

However, the opposition politicians said they were willing to participate in the commission and go along with the processes called for by the peace agreement. Godoy said this was his first meeting with Ortega in more than three years.

In an interview before the ceremony, Godoy said that while the peace plan was a good one, it had some "obscure aspects" and was already being interpreted differently by the Sandinistas and the Nicaraguan rebels, known as contras.

Godoy charged that Ortega made a "mockery" of the peace plan by telling Nicaraguans after his return from Guatemala that the democratization stipulated in the agreement was already in place here. Godoy said agreement on a cease-fire would be "one of the most complicated aspects of the accord."

Since the peace plan was signed, Ortega and other Sandinista officials have been defining a cease-fire in terms of a surrendering of arms by the contras, but the rebels have insisted on a cease-fire "in place" under regulations that allow their forces inside Nicaragua to continue receiving food, medical supplies and other "humanitarian aid."

In a lengthy televised speech Saturday, Ortega also ruled out negotiations with contra leaders.