Hong Kong (AFP) - Riot police fanned out across Hong Kong on Friday after democracy activists threatened to defy a ban on gatherings during the coronavirus pandemic -- but the streets remained largely calm.

The semi-autonomous financial hub was upended by seven months of violent protests last year, hammering its reputation for stability and leaving the city deeply divided.

Widespread arrests, the coronavirus pandemic and social distancing measures ushered in four months of comparative calm. 

But small protests have bubbled up in the past week and activists had issued calls to muster once more on May Day despite emergency anti-virus laws banning more than four people gathering in public.

Pro-democracy unions and social media posts called on people to gather in several neighbourhoods on Friday afternoon but the threat largely failed to materialise. 

Hundreds of protesters did however gather in small groups at a shopping mall in the town of Shatin, chanting slogans and holding protest flags.

Riot police soon rushed into the mall and used pepper spray to disperse the crowd.

Shops closed their shutters as police occupied the mall and cordoned off most of the area.

“I feel that the movement has been watered down because of the pandemic, but I personally think we should keep fighting." said a retired firefighter who gave his name as Lam and was at the protest.

"If we shrink back and accept our fate, then we will be living under an authoritarian regime."

Officers ramped up their presence on Friday, searching primarily young passengers at subway stations and surfacing in neighbourhoods where anti-government sentiment runs high.

Some encrypted chat groups used by protesters fretted that public demonstrations while anti-virus laws were in place might lead to mass arrests.

The pro-democracy Labour Party said one local politician was arrested for allegedly gathering with more than four people on Friday morning.

During brief rallies in malls earlier this week, activists encouraged each other to keep 1.5 metres apart and stick to small groups of four.

Riot police quickly intercepted the flashmobs, forcing them to disband as either unlawful assemblies or gatherings that breached the anti-virus measures.

Panic subsides

Three months ago, Hong Kongers were panic buying masks and hunkering down in cramped apartments as one of the first places outside mainland China to be struck by the coronavirus.

But the fear has abated in recent weeks. 

Health authorities have made impressive strides against the outbreak with just over 1,000 infections and four deaths. 

For five of the last seven days, the city of seven million has reported no new cases and authorities plan to begin easing movement restrictions in the coming weeks.

But any relaxation would come at a time of renewed political tension -- and as the anniversary of the start of last year's huge protests approaches.

Anger towards Beijing has been inflamed by the recent arrest of prominent moderate activists on charges related to the protests and senior Chinese officials announcing a greater say in how Hong Kong is run.

Last year's protests began in opposition to an eventually scrapped plan to allow extraditions to China's party-controlled courts. 

But the movement soon snowballed into a popular revolt against Beijing's rule and a call for greater freedoms.

Hong Kong's government and Beijing have shied away from any reconciliation moves, holding fast against demands for an inquiry into police conduct, an amnesty for the 7,800 people arrested during protests and universal suffrage.