The Chinese financial hub used to hold annual candlelight vigils to mark Beijing's deadly crackdown on demonstrators in and around Tiananmen Square on June 4, 1989, but those events have been banned in recent years.

Lee Cheuk-yan and Chow Hang-tung, who organised vigils as leaders of the now-defunct Hong Kong Alliance, are standing trial for "incitement to subversion", which carries a maximum penalty of 10 years in jail.

Both have pleaded not guilty and have been behind bars since 2021.

The alliance's calls to "end one-party rule" in China, a core tenet of the group since its founding in 1989, is a major focus for the prosecution during their trial.

Lee denied that he and the Alliance had intended for others to use unlawful means to undermine the party's leadership and overthrow central government organs.

"Ending one-party rule does not mean ending the Communist Party's leadership. I've said this many times," Lee told the court in answer to questioning by prosecutor Ned Lai.

Lee, wearing a black vest over a black long-sleeved shirt, smiled at supporters in the public gallery as he was led from the dock, and spoke with his lawyer through glass panels during a recess.

Lee denied he felt enmity towards the party, but said he was dissatisfied with some of its policies.

"I have no enmity in my heart, only love. Based on my love for the people, I hoped the Communist Party would reform, to let people have the rights and happiness they deserve," he said.

Fiery rhetoric denouncing the Chinese Communist Party was once seen as unremarkable in Hong Kong, but it has all but vanished after Beijing imposed a national security law in 2020 after huge and sometimes violent pro-democracy protests.

A third defendant in the case, 74-year-old Albert Ho, pleaded guilty in January and was excused from the trial, which was scheduled to last 75 days.

The trial has been condemned by Amnesty International and Human Rights Watch as an attempt at "rewriting history".