The 77-year-old founder of the now-shuttered Apple Daily newspaper has pleaded not guilty to two counts of foreign collusion, with authorities accusing him of using various platforms to lobby Western nations.

The charges are brought under the city's national security law, which Beijing imposed in 2020 after the finance hub saw huge and sometimes violent pro-democracy protests the year before.

Prosecutors on Monday cited Lai's web of foreign connections to argue he had "unwavering intent to solicit sanctions, blockades or other hostile activities" against China and Hong Kong, adding that the intent was "long-term and persistent".

In his closing arguments, prosecutor Anthony Chau highlighted Lai's trips to the United States around the time of the 2019 Hong Kong protests, including one in July where he met with then-US vice president Mike Pence.

"The court will remember that, in any event, (Lai) himself did advocate and request for sanctions, which he said was against officials and not the state," said Chau, referring to Lai's earlier testimony.

Lai has denied calling for sanctions against China and Hong Kong as a whole, and has said he never advocated separatism.

The trial was scheduled to begin its final stages last Thursday but was postponed twice: first due to bad weather and then to address Lai's medical needs.

The defence had said on Friday that Lai was experiencing heart "palpitations" and had an episode where he felt like he was "collapsing".

Chau said on Monday that Lai had been prescribed medication and was wearing a heart rate monitoring device, which was given to him on Friday.

"(Lai) has made no complaint on his heart condition or general health condition and is fit to attend court," Chau said.

Judge Esther Toh also read out a memo by a senior medical officer saying that Lai was "physically and mentally fit for court".

- Health concerns -

Concerns have been raised previously over Lai's health by his family and rights groups.

The media tycoon has been kept behind bars since December 2020, reportedly in solitary confinement, and has lost weight during that time.

The Hong Kong government said in a statement on Friday that the "medical care received by Lai Chee-ying in custody is adequate and comprehensive".

Dressed in a white shirt and pale windbreaker, Lai appeared in court on Monday without any medical equipment visible on his body.

He smiled and waved to supporters and family members in the public gallery when he entered.

He listened to the court proceedings via a set of headphones and closed his eyes for a few minutes during the morning session.

The long-running trial, which began in December 2023, is entering its final stages as Western nations and rights groups continue to call for Lai's release.

Aside from the collusion offence -- which could land him in prison for life -- Lai is also charged with "seditious publication" related to 161 articles, including op-eds carrying his byline.

Responding to human rights arguments raised by the defence, Chau said Lai had not raised any constitutionality challenges.

Elaine Pearson, Asia director at Human Rights Watch, said last week that Hong Kong should "drop the baseless charges" against Lai.

US President Donald Trump told a Fox News radio programme last week that he brought up the tycoon's case with Chinese President Xi Jinping.

"I'm going to do everything I can to save him," the outlet quoted Trump as saying.

The Hong Kong government last week said it "strongly disapproved and rejected the slanderous remarks made by external forces" regarding Lai's case.