Hong Kong has plummeted down an international press freedom chart as authorities have wielded a draconian new security law to silence critical news outlets and jail journalists, a new report said.

For two decades, media rights watchdog Reporters Without Borders has ranked countries and territories around the world by how free their press is.

Hong Kong, a regional media hub for both international and local media, has been steadily slipping down the table under Chinese rule.

In the last year alone it has plunged 68 places to 148th, sandwiching the international business hub between the Philippines and Turkey.

Norway topped the list followed by Denmark, Sweden. South Korea ranked 43nd in a press freedom index while North Korea was rated the world's worst violator. (AFP)