MANILA — Opponents of a hero’s burial for the Philippine dictator Ferdinand E. Marcos expressed outrage on Friday over his surprise, private funeral at the national cemetery in what they called a “sneaky” maneuver to flout the judicial process.

Victims of torture and imprisonment during the Marcos era had long opposed the burial in Libingan ng mga Bayani cemetery, which is reserved for national heroes, and some said they would seek to have the body removed. Hundreds of protesters began gathering after the funeral at the People’s Power Monument, which commemorates the movement that ousted Mr. Marcos in 1986.

“The stealthy and hurried manner by which the Marcos burial was orchestrated is reminiscent of the dark days of martial law,” said Franklin Drilon, the president pro tem of the Philippine Senate. “His burial is anything but noble. Even in death, he is a thief.”

Mr. Marcos held power for two decades, ruling for nearly half that time under martial law. His government is believed to have killed more than 3,000 political opponents and tortured tens of thousands more while he and his associates stole an estimated $10 billion from the country.