Hong Kong’s government is appealing a landmark court ruling that could eventually lead to foreign maids winning permanent residency in the territory.

Hong Kong’s mini-constitution allows foreign residents to apply for permanent residency after they have lived in the city for seven years — a right denied to Hong Kong’s nearly 300,000 foreign domestic helpers.

A high court judge ruled in September that provision of the law was discriminatory and unconstitutional.

But government lawyer David Pannick argued Tuesday before Hong Kong’s Court of Appeal that the ruling improperly restricts the legislature’s ability to decide who can permanently reside in the territory.

Opponents of last year’s ruling say almost half a million immigrants could overwhelm city social services such as health and education if Hong Kong’s maids were joined by their family members.

But Eman Villanueva, a spokesman for a local migrant workers group, says he is hopeful the appeals court will uphold the lower court’s ruling.

“The hope of the foreign domestic workers is for the court to decide today in favor of the overseas workers. We are also hoping that the government of Hong Kong will accept the decision wholeheartedly so that the rule of law will be upheld in Hong Kong.”

The case was first brought before the High Court by Evangeline Vallejos, a former businesswoman from the Philippines who came to Hong Kong to work as a maid in 1986.