More than 60,000 security forces in the Philippines were on alert Sunday to safeguard ballots and polling stations on the eve of the presidential election, after police reported four people killed in an outbreak of violence.

Elections are a traditionally volatile time in a country with lax gun laws and a violent political culture, but the national police said this season has been comparatively peaceful.

In one of the worst incidents, four people were killed Saturday in a gun battle between armed supporters of mayoral rivals in Magsingal town in the northern province of Ilocos Sur, said police spokesman Brigadier-General Roderick Alba. Another four were wounded.

Police in the northern province of Nueva Ecija also arrested two dozen people and seized weapons, including five M-16 rifles, a 12-gauge shotgun and 15 handguns, following a shoot-out between bodyguards of two candidates running for mayor of General Tinio.

Five people were wounded in the incident, which also left the same number of sports utility vehicles riddled with bullets, Alba said.

More than 18,000 posts, from president to town councillor, are up for grabs in the elections.

Personnel from the police, armed forces and coast guard have fanned out across the archipelago to help secure polling stations and ballots
Personnel from the police, armed forces and coast guard have fanned out across the archipelago to help secure polling stations and ballots AFP / CHAIDEER MAHYUDDIN

The son of former dictator Ferdinand Marcos looks set to win the presidential vote by a landslide, returning the clan to the pinnacle of political power.

Rights groups, Catholic church leaders and opponents see the elections as a make-or-break moment for the country's democracy, amid fears Marcos Junior could rule with a heavy fist.

Personnel from the police, armed forces and coast guard have fanned out across the archipelago to help secure polling stations and ballots, escort election officials and guard checkpoints.

The security deployment involves around 48,000 soldiers and 16,000 police, officials said.

"Based on our planning... we are confident that we'll have a secure and orderly election," said armed forces spokesman Colonel Ramon Zagala.

There have been 16 "validated election-related incidents" since January 9, including four shootings and a "slight illegal detention", Alba said.

Philippines presidential candidate Ferdinand Marcos Jr, the son of the former dictator, looks set to win by a landslide
Philippines presidential candidate Ferdinand Marcos Jr, the son of the former dictator, looks set to win by a landslide AFP / JAM STA ROSA

That compares with 133 incidents during the 2016 presidential elections and 60 in the 2019 mid-term polls.

Police spokeswoman Colonel Jean Fajardo attributed the sharp drop to a heightened security presence, as well as military and police operations targeting "loose firearms" and private armed groups.

The election commission largely prohibits the carrying of weapons during the election period that lasts until June 8.

Experts say the explosion of social media, which has made it easier to report incidents, and the growing domination of political dynasties, which smother electoral competition, have helped tamp down election violence.

In the country's deadliest single incident of political violence on record, 58 people were massacred in 2009 as gunmen allegedly belonging to a local warlord in the southern Philippines attacked a group of people to stop a rival filing his election candidacy.

Thirty-two of the victims were journalists covering the contest, making the attack also the deadliest on record against media professionals.

The introduction of electronic voting in 2010 has made it harder for widespread vote-rigging that has historically plagued Philippine elections.

But Marcos Jr, who still insists he was cheated of victory in the 2016 vice presidential race, has warned of electoral fraud in these polls and urged his supporters to be alert.

"We will win as long as you stay awake on Monday so there won't be another tragedy," Marcos Jr told hundreds of thousands of fans at his final campaign rally on Saturday.

"Many undesirable things happen if we stop paying attention."