Crowds gathered on a highway in Manila, the same area that millions flocked to 31 years ago in a peaceful revolt that led to Marcos' ouster.
The so-called People Power Revolution three decades ago attracted government leaders, church groups and civilians in a series of protests that ended Marcos' 14-year military rule marred by human rights violations.
Saturday's event was a commemoration and a symbolic protest against Duterte. At another rally a few miles away, pro-Duterte supporters listened to Christian songs and testimonies of former addicts.
The protest comes amid a surge in drug-related deaths suspected of being sanctioned by Duterte's administration, and a day after the arrest of one of the most vocal critics of his anti-drug campaign
Allies of detained Sen. Leila de Lima said her arrest Friday over "trumped up" charges signals the slow demise of democracy, and is meant to silence opposition to the drug war the President has waged
since taking office in June.
De Lima became the subject of probes launched by Duterte's political allies after the senator initiated a Senate inquiry into alleged state-sanctioned killings. A Senate committee, led by a Duterte ally, decided in October to drop its inquiry
into the extrajudicial killings.
Flowers help ease tensions
Commotion ensued Saturday between pro- and anti-Duterte protesters after Filipino musician Jim Paredes confronted the Duterte supporters who had showed up on the sidelines of the rally. Authorities immediately intervened.
Seven men who were part of the Duterte Youth group were berated. Others shooed them away with profanity-laden tirades.
Tensions eased when an anti-Duterte supporter handed flowers to the seven men.
Simon Valencia, 28, said the flowers were a gesture on his part to support the group's freedom of expression.
Duterte 'waging a war on democracy'
Former Philippine President Benigno "Noynoy" Aquino III, son of the late pro-democracy icon Corazon Aquino, was among those attending Saturday's event. His mother was catapulted into power after Marcos' ouster.
Benigno Aquino said this year's commemoration is more than an act of remembrance. "(The) fight is not over if we are not ready to defend our rights," he told reporters.
Last year, Duterte ordered the honorary burial of Marcos' remains at a state cemetery reserved for war heroes, national artists and those who bring distinction to the country. The law refers to those interred at the Heroes' Cemetery as men and women who are "worthy of emulation" by generations of Filipinos.
"The Marcoses -- through Duterte -- are erasing the Filipino people's memory and moral standards by burying the former dictator as a hero," said human rights lawyer Jesus Falcis, who was among those who had petitioned the Philippine Supreme Court to try and stop the burial.
"Duterte himself is waging a war on democracy -- not just on the poor and drugs -- with his creeping authoritarianism," said Falcis, who came to Saturday's rally with friends.
Duterte won the presidency on a platform of cracking down on crime, particularly illegal drugs. Since taking office, his police force has waged a bloody war on drug dealers and users, resulting in the deaths of thousands of suspects
at the hands of police and vigilantes.