Police intelligence agents and members of the Presidential Anti-Organized Crime Commission raided five hideouts of a syndicate in the northern provinces of Bulacan and Nueva Ecija and arrested four alleged members and killed one suspect, national police intelligence director Charles Calima said.
The guns-for-hire syndicate is suspected of involvement in past political killings, Calima said.
Officers seized pistols, a grenade, ammunition and a motorcycle, and four of the guns would be tested to check if they had been used in past attacks, Calima said.
More than 18,000 congressional and local positions will be decided in the elections next May, and violence and fraud are an ugly hallmark of past Philippine elections.
The Philippines shifted to automated elections for the first time in the 2010 presidential elections to produce results more rapidly and prevent violence and fraud from arising during the slow hand-counting of votes that took months to complete in the past.
"It's now hard to cheat because of the automated elections," Calima said. "The concern is some candidates may opt to eliminate rivals with these guns for hire."
A hired gunman could get as much as 4 million pesos ($95,200) to stage a killing, according to police.
President Benigno Aquino III has ordered the national police to take steps to curb elections violence -- a tough feat in an impoverished country awashed with tens of thousands of unlicensed firearms and burdened with warlord clans and powerful provincial politicians with private armies.
In the country's worst political violence, 57 people were herded from a convoy at gunpoint and gunned down en masse in southern Maguindanao province in 2009 in what officials say was an attempt by a ruling clan to prevent a rival family from challenging its political control in the region in an elections. Among those killed were 31 media workers.
Prominent members of the clan have been arrested and are being tried for the massacre.