SWEETWATER, FLA., NOV. 12 -- Republican presidential candidate Marion G. (Pat) Robertson denounced Nicaragua's Sandinista government today before an appreciative audience made up mostly of Nicaraguan exiles and said he would encourage the formation of a Nicaraguan government in exile.

The former television evangelist won cheers from some 50 supporters at a Nicaraguan steakhouse when he said he would then "withdraw recognition of the Sandinista government."

Robertson said he would "invoke the Monroe Doctrine and tell the Soviets, Bulgarians, Cubans . . . this is our hemisphere and they should get out of it."

After his address, he told reporters he is opposed to the Central American peace plan put forth by Costa Rican President Oscar Arias and signed Aug. 7 by all five Central American presidents. It sets a January deadline for complying with the plan, which calls for a cease-fire by Nicaraguan government forces and the contra rebels.

"It is an illusory peace that leaves a communist dictatorship in power," Robertson said.

Robertson also said certain groups have grown too influential in U.S. society.

"I have no intention of surrendering the streets of America to the militant homosexuals and the drug pushers," he said. "If it's a fight they want, it's a fight they'll get. But we are not going to give over the greatness of this nation to the forces of decay and disintegration."

Robertson pledged to name conservatives to government posts. He said he would veto any bill providing federal funds to Planned Parenthood, and called for a constitutional amendment to ban abortion.