June 4 vigil organizers say they will enter Victoria Park that night even without police approval to hold the event.
Hong Kong Alliance in Support of Patriotic Democratic Movements in China members said "end one-party rule" chants would continue despite uncertainty over whether the signature slogan would breach the national security law just approved.
A meeting with the police yesterday over the application to organize the vigil marking the 1989 Tiananmen crackdown proved unfruitful.
"The police are not sincere [in trying to come up with a solution]," alliance chairman Lee Cheuk-yan said, with officers refusing to give a concrete reply over whether an assembly would be allowed if social-distancing rules were observed.
The eight-person cap on the number of people in gatherings has been extended till June 4, a decision Chief Executive Carrie Lam Cheng Yuet-ngor said wasn't political.
"If an assembly won't be allowed, then why should we discuss this further?" Lee said, adding officers also failed to provide alternatives if the assembly was banned.
"With or without [police] approval, the alliance will be entering Victoria Park at 8pm to light candles," Lee said.
In case of a police objection, the public is urged to join an "online vigil" to observe silence at 8.09pm - to symbolize 1989.
Police have objected to plans for a June 4 march on Sunday. An appeal to the decision was also turned down.
The alliance said it will shift to setting up street booths across different districts.
The June 4 vigil in Victoria Park has never not been held since 1990.