Although the clashes were not as intense as some previous occasions, the Mong Kok shopping district witnessed radical protesters blocking roads, igniting fires and interrupting traffic, local media outlets reported.
In response, the police fired teargas and rubber bullets to disperse the protesters, it confirmed in a statement.
In the neighboring Yau Ma Tei district, at least five rounds of teargas were fired in the early hours of Wednesday, just after the police warned the protesters that they were participating in an illegal assembly, Efe news reported.
Earlier, more than 1,000 people formed human chains in different districts to block roads and chant slogans, while other protesters entered shopping malls to urge people to not forget what had happened in 2019 and continue protesting in 2020.
Meanwhile, thousands of people are expected to gather Wednesday for a march called by the Civil Human Rights Front, a group that has mobilized more than one million pro-democracy protesters on earlier occasions.
Although the police gave permission for the march, it warned in a video posted on its website that protesters would "not get public support" if they used violence and officers would be forced to arrest them.
Demonstrations in Hong Kong began in June following a controversial extradition bill, already withdrawn by the government, but have mutated into a movement seeking to improve Hong Kong's democratic mechanisms and safeguard the region's partial autonomy from Beijing.
Some demonstrators have opted for more radical tactics than peaceful civil disobedience and violent clashes with the police have been frequent.
Months of protests have plunged Hong Kong's economy into recession for the first time in a decade, having contracted by 2.9 per cent in the third quarter, due to falling imports and exports, retail sales and declining tourism.
( With inputs from IANS )