Hong Kong's top court on Monday threw out a landmark case that would have given hundreds of thousands of foreign maids the right to seek permanent residency, ending a legal battle that split the city.

In rejecting the bid to give maids the same residency rights as other foreigners, the Court of Final Appeal ruled that there was no need to refer the case to Beijing for a final say, which would have sparked new controversy.

Authorities in semi-autonomous Hong Kong had suggested enlisting the advice of the Chinese central government on the immigration question, sparking warnings that they were jeopardising the territory's cherished judicial independence.

In the event, the top court drew a line under the matter by rejecting the two-year legal battle brought by Filipina maid Evangeline Banao Vallejos, a mother of five who has lived in Hong Kong since 1986.

"With the court's ruling today, it gave its judicial seal to unfair treatment and the social exclusion of foreign domestic workers in Hong Kong," Eman Villanueva, spokesman for the Asian Migrants' Coordinating Body, said outside.

Vallejos won a High Court ruling in 2011 granting her the right to request permanent residency status, which most foreigners can seek after seven years' stay but which is denied to the city's 300,000 foreign domestic helpers.

Labour rights activists had hailed the ruling as a big step for equal rights for maids, who are a backbone of society in richer Asian economies and a financial lifeline to their home nations, notably the Philippines and Indonesia.

But the Court of Final Appeal sided with an appeal lodged by the Hong Kong government, which warned that the ruling would swamp the cramped city's population of seven million.

"The FDH (foreign domestic helper) is obliged to return to the country of origin at the end of the contract, and is told from the outset that admission is not for the purposes of settlement and that dependents cannot be brought to reside in Hong Kong," the appeals court said in a written judgement.

The ruling means that maids will continue to be specifically excluded from eligibility to settle in Hong Kong, which would give them access to voting rights and the right to live in the former British colony without a work visa.

Mark Daly, a lawyer for Vallejos, said his client was "speechless but calmly resigned and said 'no problem'".

Hong Kong's foreign maids receive a minimum wage of HK$3,920 (US$505) a month and benefits such as one guaranteed day off a week, but rights groups say they face discrimination and a lack of legal protection from abusive employers.

The Vallejos case threw new light on Hong Kong's often uneasy relationship with authorities in mainland China and the full extent of the territory's autonomy under its mini-constitution, known as the Basic Law.

While there have been repeated outcries from the Hong Kong public against perceived mainland interference, the southern city's own government stands accused of undermining its autonomy by seeking Beijing's adjudication.

That was the case regarding a long-running legal question about children of Hong Kong permanent residents from mainland China, which like the foreign maids case had created anxiety over the potential strain on the city.