MANILA, Jan 22 (Reuters) - Philippine President Gloria Macapagal Arroyo on Monday ordered the labour department to block workers from travelling to Nigeria after the kidnapping of six Filipino sailors from a cargo ship in the West African country. The Nigerian government has begun talks to secure the early release of the six Filipino seamen, taken from a German-operated ship last week in a southern oil producing delta. "The president has ordered a temporary halt to deployments to Nigeria until the security of our nationals is guaranteed," said Arroyo's spokesman, Ignacio Bunye, adding she was monitoring the situation and coordinating with the Nigerian government. Quoting a report from the Department of Foreign Affairs, Bunye said the six Filipino sailors were part of the 14-member crew of the vessel operated by Germany's Baco-Liner, based in Duisburg, which runs between Europe and West African ports. More than 8 million Filipinos work overseas, many on board ships or as nurses or maids.