Christmas Day in Hong Kong has seen no let-up in clashes between police and pro-democracy protesters.

The police used tear gas and pepper spray as demonstrators gathered again in a number of shopping districts, the BBC reports.

The latest protests began on Christmas Eve, with police battling activists who were throwing petrol bombs.

Hong Kong leader Carrie Lam said many residents and tourists had seen their Christmas celebrations "ruined by a group of reckless and selfish rioters".

"Such illegal acts have not only dampened the festive mood but also adversely affected local businesses," she said in a Facebook post on Wednesday, December 25.

The protests began in June, focusing on a bill that would have allowed the extradition of suspects to mainland China.

The bill was later withdrawn, but demonstrations have since evolved into a broader movement demanding investigations into police brutality and democratic reform.

The protests, which had been largely peaceful in recent weeks, have turned more confrontational over the festive season.

On Wednesday hundreds of activists marched through shopping centres shouting slogans such as "Liberate Hong Kong! Revolution of our times!" Police arrested several people after using pepper spray.

The clashes were on a lesser scale than Tuesday, when activists set up barricades and threw petrol bombs across the city, while police used pepper spray and batons.