The immigration authorities of the Philippines on Wednesday pledged to rein in the growing trend of Filipinos illegally working abroad on "tourist visas", especially in Singapore, Dubai of United Arab Emirates and China's Hong Kong.

"We have to make sure that our Filipino workers are protected from possible abuse and exploitation in foreign lands," an on-line report of the Philippine Daily Inquirer quoted Marcelino Libanan, Commissioner of the Bureau of Immigration, as saying.

A "tourist worker" is one who goes abroad as a tourist but actually has the intention of working in his or her country of destination, Libanan said, adding that the practice is aimed to circumvent the government requirement of securing clearance from the Philippine Overseas Employment Administration (POEA), he said.

Libanan also said a stricter procedure would be devised to ensure no "tourist workers" that could sneak out of the country.

About 300 of the 442 passengers who were barred from leaving the country since June were suspected "tourist workers," he said.