A throng of mostly female domestic helpers marched through the city to the Philippine consulate to present a petition calling on President Arroyo to scrap the proposal.
If passed, the law will require maids who work overseas to undergo a two or three week "competency training and assessment program" recognized by the Overseas Workers’ Welfare Administration at a cost of P10,000-15,000 ($215 to $320).
Maids in Hong Kong typically earn about 450 dollars a month.
Dolores Balladares, chairman of the Asian Migrants Coordinating Body (AMCB), which has organized the rally, described the proposal as "extortion."
"They are taking advantage of the overseas workers," said Balladares.
In a statement, the Department of Labor and Employment said it had issued a resolution relaxing the policy so that it would apply only to newly-hired maids.
Balladares dismissed the adjustment as meaningless.
"This is just a means of softening the blow after the angry protests that greeted this proposal," she said. "It is a hollow gesture."
In Manila, Labor Secretary Arturo Brion defended the law as part of reforms to give maids better protection amid a number of high-profile cases of abuse against maids, especially in Saudi Arabia and Singapore.
"The reforms that we have been implementing are for the long-term and would place the (maids) on a better footing against abuse and exploitation abroad," he said.
"I appeal to our (overseas Filipino workers) not to be misled by some quarters, in their veiled attempt to discredit the reforms that we have set in place," Brion said.
Filipinos make up Hong Kong’s largest immigrant community, with some 120,000 maids working in the city.
While the Manila government says about 1.5 million of its citizens work overseas as domestic helpers, an unofficial tally by the AMCB puts the figure closer to 10 million.