The Philippines said on Wednesday it would be discouraging employment agencies from hiring Filipinos for ships operating off the Somali coast.

The move does not amount to an outright ban, however, which may not work since Filipino seamen are not obliged to tell the government about their ship's routes, President Arroyo's chief aide, Executive Secretary Eduardo Ermita, said.

The country's labor department will ask agencies not to hire "Filipino seamen that will be plying the route of the Gulf of Aden and in the area where this hijacking or kidnapping is happening," Ermita said.

The Philippines is the world's leading supplier of shipping crews, with over 350,000 seamen manning oil tankers, luxury liners and passenger vessels worldwide, official statistics show.

There are 100 Filipino seamen aboard seven vessels in the hands of Somali pirates.

This includes 22 Filipino crewmen aboard the Greek vessel Irene EM seized by pirates on Tuesday, Ermita said.

"At the moment, we have not gotten any feedback as to the advisability of issuing an official ban for Filipino seamen going there," Ermita said, conceding that the situation had become "very alarming".

The Philippines, he said, is prepared to "take an active part" should the United Nations decide to send in a multinational force to help patrol the waters in Somalia and rescue the hostages.

But there has been no such proposal at the moment, Ermita said.

On Tuesday, a leading seafarers' group in Manila called on the government to rally the international community for a more proactive stand against piracy in Somalia, including calls for a possible 'expeditionary force'.

Ermita said in the meantime, the Philippines was content to let employment agencies and shipping firms conduct their own negotiations with pirates.

"You can see that the motive really other than just gaining mileage through media is ransom," he said. "And the manning agencies as well as ship owners have been willing to pay."