Philippine President Gloria Arroyo on Monday slapped a temporary ban on workers travelling to Nigeria for employment after the weekend kidnapping of six Filipinos.
The Philippines is one of the world's biggest exporters of workers and their remittances home are crucial to the country's economic stability.
But Arroyo's spokesman Ignacio Bunye said in a statement that the order to halt workers travelling to Nigeria was for safety reasons.
"The president has ordered a temporary halt to deployments to Nigeria until the security of our nationals is guaranteed," Bunye said.
"The president is monitoring the situation and the Department of Foreign Affairs is coordinating with the Nigerian authorities to ensure the safety and secure the release of the kidnapped victims," the statement added.
Unknown assailants took six Filipino oil workers and one local staffer hostage on a cargo ship on Saturday in the Niger Delta, the latest in a string of kidnappings in the epicentre of Nigeria's multi-billion-dollar oil industry.
"The vessel is still being held with six Filipinos in it. We understand they are OK. (State) Governor James Ibori is already intervening on the matter," a spokesman for Delta State government, Ozoene Sheddy, said at the weekend.
"There were 14 crew members on board but only six were taken," Sheddy said, adding that the cargo ship was heading for the port of Warri, Delta State's capital.
No group has so far directly claimed responsibility for the latest attack, but a prominent separatist group in the region said Sunday that members of a local community had seized the Filipinos.
"They were taken by a community in that vicinity. The community plans to explain their reason for their abduction today," a spokesman for the Movement for the Emancipation of the Niger Delta (MEND) said.
The latest kidnapping brings to nine the number of foreigners currently being held hostage in the volatile region.
More than eight million Filipinos -- about a tenth of the population of 86 million -- live and work in over 190 countries and territories.
In the first 11 months of last year they sent home 11.44 billion dollars, contributing about 10 percent of the Philippines' gross domestic product.
Philippine foreign ministry spokesman Ed Malaya said some 3,900 Filipinos were employed in Nigeria at the end of 2006.
"It is one of the biggest employers of Filipino workers in Africa," he told AFP.
He said the Philippine Overseas Employment Administration (POEA) would stop issuing authorisation for companies to hire Filipino workers to work in Nigeria until further notice.
"Our embassy in Nigeria is working closely with the state and federal authorities to resolve the situation and to seek the safe return of our people," he said.
As of early Monday, the POEA had not yet issued any advisories or warnings on its website about the possible dangers of working in Nigeria.
It listed hundreds of jobs available in the country, ranging from accountants to engineers. Most of the positions were in the oil industry.
According to Malaya, MEND is believed to have been behind the kidnapping.
There has been a sharp rise in the number of kidnappings and attacks on oil installations in the Niger Delta since the beginning of 2006.
Last year more than 60 foreigners, mostly oil workers, were kidnapped, and dozens of Nigerians were killed by militants and bandits.
The people of the delta complain that while their region generates 95 percent of Nigeria's foreign currency earnings, they have little to show for this in terms of development or living standards.