The Contadora peace process has been left in limbo by yesterday's cancellation of the latest round of talks as a result of a dispute between Nicaragua and Costa Rica over a political asylum case.

Foreign ministers of Honduras and El Salvador joined their Costa Rican counterpart at a press conference in San Jose yesterday and announced that they would not attend the meeting scheduled for today.

The decisions by the three countries caused the Contadora nations -- Mexico, Colombia, Panama and Venezuela -- to cancel the meeting, which was to be held in Panama. The four countries first met on the Panamanian island of Contadora in January 1983 in search of political solutions to the region's conflicts.

Yesterday's cancellation has caused concern among diplomats here about the future of the process, which has been credited with defusing some of tensions.

Foreign Minister Miguel D'Escoto charged the Reagan administration today with influencing the decisions of its allies in the region to boycott the meeting. He accused the United States, which recently broke off bilateral talks with Nicaragua, of trying to wreck the Contadora negotiations and continue what he called "irresponsible and warlike policies."

A State Department spokesman reiterated U.S. support for Contadora and said Costa Rica had sought to conciliate its differences with the Sandinistas. "It is difficult to avoid the conclusion that Nicaragua is using the case to block further deliberations within the Contadora process," he said.

Costa Rica -- now with Honduran and Salvadoran support -- has said it would not attend another Contadora meeting until resolution of the case of Nicaraguan Jose Urbina Lara, who took refuge in the Costa Rican Embassy here last August and asked political asylum.

Urbina Lara earlier had refused to answer a draft notice of the Sandinista Popular Army.

On Christmas Eve, according to the Nicaraguan government, a woman friend of Urbina Lara drove up in front of the embassy, and he came out of the building, left the embassy grounds and was trying to enter the car and get away when he was detained by Sandinista police. It says that in a scuffle a gun went off accidentally, wounding Urbina Lara in the leg.

Costa Rica charges that Urbina Lara never left the embassy grounds, but was lured out of the building by a woman acquaintance working with the Sandinistas and was then grabbed by Sandinista guards. Sandinista guards shot him to capture him, by this version. He is still in custody.

Latin American diplomatic convention prohibits law enforcement officials from entering embassy grounds without permission, and Costa Rica insists that Urbina Lara must be returned to them.

Representatives of two Contadora countries, who asked not be named, said this week that an agreement had been reached whereby the Sandinistas would return Urbina Lara and the Costa Ricans would attend the Contadora meeting. But those diplomats said the agreement was called off at the last moment.

Those envoys could not say why the agreement fell through, but diplomats here speculated that while more moderate members of the Sandinista leadership were willing to deliver Urbina Lara, hard-liners may have balked.

Alejandro Bendana, first secretary of the Nicaraguan Foreign Ministry, said the Sandinistas had linked the case to their requests that Costa Rica deport members of anti-Sandinista rebel forces there, and had not received acceptable responses.