The flag-raising ceremony that took place at the Hong Kong Convention and Exhibition Centre where Acting Chief Executive Matthew Cheung called on people to cherish the city's "hard-earned stability" and work together to rekindle hope and confidence to start afresh, the South China Morning Post reported.
Cheung said the entire administration was working hard for the policy address, due later this month, trying to address deep-rooted problems in the city.
The city's Chief Executive Carrie Lam was in Beijing where she witnessed the armed forces parade, deemed as China's biggest ever.
Meanwhile, a "black balloon flash mob" in Tsim Sha Tsui, which would involve popping balloons in protest against the flag raising ceremony, was quickly quelled by the police.
Police officers found balloons in a private car and two trucks at around 4 a.m. and arrested five people.
Scuffles broke out near the Hong Kong Convention and Exhibition Centre between League of Social Democrat activists and a group of people criticising their slogans. The police used pepper spray while trying to separate the two groups.
Ahead of citywide illegal rallies on Tuesday afternoon, the Mass Transit Railway (MTR) Corporation has closed 11 stations.
More than 25 shopping malls in different districts were closed for safety reasons.
Hong Kong has emerged from 17 straight weekends of protest, triggered by the now-withdrawn extradition bill, which would have allowed criminal suspects to be sent back to mainland China.
( With inputs from IANS )