MIAMI, SEPT. 1 -- Senate Minority Leader Robert J. Dole (R-Kan.), who exchanged sharp words Monday in Nicaragua with President Daniel Ortega, said today he will continue to urge that President Reagan request new aid for the Nicaraguan rebels by Sept. 30.

Dole, who is expected to announce his candidacy for president later this year, also proposed renewed bilateral talks between Washington and Managua "with reference to the Soviet threat" in Nicaragua. A first round of talks with the leftist Nicaraguan government was suspended after less than a year in 1985.

Dole and four other Republican senators, returning from a two-day visit to three Central American countries, expressed their support for two positions that appear to conflict: continued U.S. military aid for the Nicaraguan rebels, known as contras, and a peace plan signed Aug. 7 by five Central American presidents.

The peace plan calls for an end to foreign aid to rebel groups in Central America by Nov. 7 as well as for full democracy in Sandinista-controlled Nicaragua.

Today Dole said he doubts Ortega will "give up a share of power," which the senator interprets the peace plan as requiring Ortega to do. Dole said he would ask Reagan to devise a formula to make new aid ready for the contras after Nov. 7 if the peace plan should fail. Dole and some contra leaders have previously suggested a plan in which renewed military aid would be put into an account not to be sent to the contras unless the peace process fails.

"We didn't go down there to torpedo anything. We went to reassure some people we want to give this peace initiative a chance, and at the same time we don't want to desert our friends, the contras," Dole said.

Ortega unexpectedly summoned the press to his meeting Monday with the American senators and berated Dole, accusing him of making the trip solely to strengthen his push for contra aid.

Ortega "attempted to use us as props in a circus atmosphere," Dole said at an afternoon news conference here. During the senators' four-hour stay in Nicaragua, Dole, Thad Cochran (Miss.), John McCain (Ariz.), Steve Symms (Idaho) and David K. Karnes (Neb.) also met with relatives of political prisoners and with the Roman Catholic leader, Cardinal Miguel Obando y Bravo, the Sandinistas' most powerful opponent.

The senators made it clear they reciprocated Ortega's hostility. McCain told Ortega if Nicaragua wants to talk directly with Reagan because he is "the contras' boss," as Ortega has said, then the United States should talk with Cuban ruler Fidel Castro, "since obviously he is Ortega's boss," McCain said.

McCain added: "He was not too pleased."

"It was quite a negative meeting," said Rep. Peter H. Kostmayer (D-Pa.), who also attended the session, in a telephone interview from Costa Rica.

McCain and Symms said they visited a contra military camp in Honduras Monday morning. The Aug. 7 peace plan, signed in Guatemala, calls for such bases to be shut down. The Honduran government has denied it has any contra camps in its territory.

Ortega's questioning of Dole's political motives was based in part on the senator's decision to publish "an open letter to Ortega" that was highly critical the day before the two were to meet, containing points Dole could have made privately.

{Responding to reporters' questions today, Dole told The Miami Herald that a Republican camera crew had accompanied him and the other senators on the trip and had filmed the acrimonious exchange between him and Ortega. Asked whether the film might become part of his presidential campaign commercials, Dole said, "It could. Why? Is that illegal?"}