The Reagan administration has stepped up its public criticisms of deposed Philippine president Ferdinand Marcos for using his Hawaiian exile to foment dissent against the government of Corazon Aquino, as protests by Marcos loyalists in the Philippines have grown larger and more violent.

A State Department spokesman said yesterday that the administration had strong indications that Marcos is financing the protests. "We don't like it," the spokesman said, adding that Marcos "has been warned. He's been told. And he keeps on; it gets worse.

"We've started talking publicly about what we had previously been talking about privately -- that is, it's one thing to speak your mind and another to engage in activities designed to bring down the government of a friendly state."

Marcos loyalists have staged increasingly violent demonstrations almost every weekend since Aquino came to power in a popularly backed military uprising in February. Wednesday night, 1,000 to 3,000 Marcos supporters gathered at Camp Aguinaldo, site of the February revolt, following rumors that Aquino had been overthrown by her defense minister, Juan Ponce Enrile, a Marcos holdover.

Aquino later appeared at the presidential palace in Manila to brush aside the coup rumors and announce that "everything is still okay," Washington Post special correspondent Abby Tan reported. Aquino accused Marcos of using "disinformation or misinformation" to fuel the coup rumors, which began when Enrile left a Wednesday cabinet meeting before it had ended.

Philippine officials here also accused Marcos of financing anti-Aquino demonstrations in this country. Small pro-Marcos demonstrations have occurred in Hawaii, Los Angeles, Chicago and New York, and Philippine Embassy officials said they had evidence that Marcos was coordinating and financing these efforts.

Philippine government officials said they see the continuing demonstrations more as a nuisance than as a serious threat to Aquino. "I don't think there's any danger they can destabilize her," embassy spokesman Benedicto David said. "That's why it's important to go after Marcos' hidden wealth, to de-fang this guy . . . . He's a pest."

Trade and industry minister Jose Concepcion, who arrived here yesterday for talks on liberalizing U.S. quotas on Philippine sugar and textiles, said: "I think the United States can put stronger pressure on President Marcos."

Marcos "has been sending a number of distortions," Concepcion said, adding: "I think he should now lay off and allow the Aquino government -- a government elected by the people -- the opportunity to carry on."