Sixteen Filipinos have been accounted for and four others are still missing since Algerian special forces stormed the plant on Saturday to end the siege, Foreign Affairs spokesman Raul Hernandez told reporters.
He said the information came from Algerian authorities, which expressed their condolences to the Philippine government and the victims' families.
"The deaths of the six Filipinos were a direct result of the hostage-taking incident in the area and mostly by gunshot wounds and the effects of the explosions," Hernandez said.
He said his office was notifying the families and arranging for the repatriation of the victims' remains, while the government was focused on finding the missing four Filipinos. A team from the Philippine Embassy in neighboring Libya, which covers Algeria, was on the ground in that country.
Four Filipino survivors were treated in a hospital in Algiers, Hernandez said.
Most of the workers were employed by Japanese companies, he said.
A total of 1,780 Filipinos work in Algeria. They are part of 10 million overseas workers, or 10 percent of the population employed abroad.