Hong Kong's top court has started hearing a challenge to the right of abode law that could pave the way for thousands of foreign maids to claim residency.
The Court of Final Appeal hearing centres on Filipina maid Evangeline Banao Vallejos, who won a High Court ruling in 2011 granting her the right to request permanent residency.
The government appealed against that ruling last March, successfully arguing authorities had power to decide who was eligible for residency and that restrictions on maids were not unconstitutional and discriminatory.
Campaigners for the rights of migrant workers argue that Hong Kong's 300,000 maids, mostly from the Philippines and Indonesia, should not be treated any differently from other foreigners who flock to Hong Kong and are mostly eligible to apply for permanent residency.
The hearing in the Court of Final Appeal is expected to last up to three days but a decision may not be handed down for some time.
Government officials have warned that making domestic helpers eligible for permanent residency could open the floodgates to hundreds of thousands of residency requests from maids, some of whom have lived in Hong Kong for decades.