Police have signed off a march and rally organised by the Civil Human Rights Front - which is behind the city's largest anti-government demonstrations - for the first time since August, reports the South China Morning Post newspaper.
Chris Tang, who was promoted to police commissioner last month, is expected to be in charge of operations on Sunday.
He warned that the force would intervene if protesters ignored his pleas for a "peaceful and orderly" demonstration.
The mass rally and march on Sunday is the first organised by the front to secure permission from police since August 18.
The force has rejected several applications in recent months for the pro-democracy group's events, on the grounds of public safety and the risk of violence.
"I hope the marchers can show the whole city, or the whole world, that we are able to participate in a rally peacefully and orderly," Tang added.
Meanwhile, the Front is expected to announce more details of the march and rally later on Friday, said the South China Morning Post.
The pro-democracy group has been behind some of the biggest protests since the political crisis began in June, including one on June 16 which drew an estimated 2 million people.
Hong Kong has been rattled by nearly six months of anti-government protests, which have often descended into violence and paralysed the city's transport system.
What started out earlier this year as peaceful protests triggered by the now-withdrawn extradition bill have developed into a wider anti-government movement, with increasingly violent clashes between police and protesters, as well as among residents.
( With inputs from IANS )