Many Hong Kong residents are scouring for new jobs and homes overseas, fearful that a new national security law imposed by Beijing will crush coveted rights not enjoyed on the mainland and herald a new authoritarian era for China's freest city.

Beijing bypassed the city's legislature to approve the law directly this week, heightening anxiety over its impact on the former British colony of 7.4 million people that is a global financial hub and gateway for capital flows in-and-out of China.

Immigration lawyers and consultants, property agents and recruitment groups from Australia to Canada all said they were inundated with inquiries from Hong Kong residents.