According to the foreign ministry in Manila, diplomats from the Philippine embassy in Baghdad had been asked to mediate in a disagreement between the workers and KBR sub-contractor Prime Projects International (PPI).
KBR and PPI are involved in operations in Taji, north of Baghdad, where about 300 Filipinos work at Camp Cook, a former Republican Guard stronghold now serving as a US base.
KBR spokeswoman D. Nikki Wheeler told AFP that while not directly involved in the matter, her company had intervened to help resolve "concerns and misunderstandings" about the workers’ contracts.
"KBR immediately addressed this issue and, after receiving clarification, the PPI team elected to resume work," she said.
According to Foreign Secretary Alberto Romulo, the Department of Foreign Affairs had received reports of Filipinos complaining that working conditions and hours on the base violated their contracts.
KBR manages non-combat-related operations of US military installations in Iraq, while PPI recruits Filipino workers for them.
The Philippines is the biggest supplier of manpower for US-led coalition forces, with an estimated 6,000 Filipinos employed in various camps.