Hong Kong's top court has denied bail to media tycoon and Beijing critic Jimmy Lai, the most high-profile person charged under the city's national security law.
Lai has been in custody since December 3, except for when released on bail for about a week late last year.
He was granted a $HK10 million ($A1.7 million) bail by a lower court on December 23 only for the Court of Final Appeal (CFA) to bring him back into custody on December 31 for another hearing.
His return was related to Article 42 of the security law, which says "no bail shall be granted to a criminal suspect or defendant unless the judge has sufficient grounds for believing that the criminal suspect or defendant will not continue to commit acts endangering national security".
On Tuesday, the CFA said the lower court applied an "erroneous line of reasoning" and "misconstrued" Article 42. The decision was unanimous.
Lai was arrested in August when about 200 police officers raided his Apple Daily tabloid newspaper.
Beijing imposed the sweeping national security law on the former British colony in June 2020 after months of pro-democracy protests.
It punishes anything China considers subversion, secession, terrorism or collusion with foreign forces with up to life in prison.
Critics say it is aimed at crushing dissent and it erodes freedoms in the semi-autonomous, Chinese-ruled city. Its supporters say it restores stability after months of unrest.
Prosecutors have accused Lai of breaching the law over statements he made on July 30 and August 18, in which they allege he requested foreign interference in Hong Kong's affairs.
Under the new law, the onus is on the defendant to prove they would not be a national security threat if released on bail.
Under Hong Kong's common law-based legal system, the onus has traditionally been on the prosecution to prove its case.
The tycoon has been a frequent visitor to Washington, meeting with officials, including former Secretary of State Mike Pompeo, to rally support for Hong Kong democracy, prompting Beijing to label him a "traitor".
Lai stepped down last year as chairman of Next Digital , which publishes Apple Daily, a popular tabloid newspaper known for its feisty and critical coverage of China and Hong Kong.