The 78-year-old founder of the now-defunct Apple Daily newspaper was found guilty in December of foreign collusion under the city's sweeping national security law, which Beijing imposed following huge and sometimes violent pro-democracy protests in 2019.

He was also found guilty of one count of seditious publication, and could face life in prison.

Lai, a British citizen, has been behind bars since 2020, and multiple Western nations, including the United States and Britain, have called for his release.

The judges wrote in their 856-page verdict in December that Lai "harboured his resentment and hatred of (China) for many of his adult years" and sought the "downfall of the Chinese Communist Party".

Amnesty International said Lai's conviction in December "feels like the death knell for press freedom in Hong Kong", while the Committee to Protect Journalists called it a "sham".

Hong Kong's government has rejected the accusations, saying Lai's case "has nothing to do with freedom of speech and of the press".

Collusion offences "of a grave nature" will result in a prison term of between 10 years and life, while sedition comes with a maximum of two years.