Hong Kong's Lunar New Year celebration descended into chaotic scenes as protesters and police, who fired warning shots into the air, clashed over a street market selling fish balls and other local holiday delicacies, leaving dozens injured and arrested.

The violence is the worst in Hong Kong since pro-democracy protests rocked the city in 2014, leaving a growing trust gap between the public and authorities.

Activists angered over authorities' attempts to crack down on the food hawkers in a crowded Kowloon neighbourhood held running battles with police into the early morning hours of Tuesday.

Protesters pelted officers with bottles and pieces of trash. Some threw garbage cans, plastic safety barriers and wood from shipping pallets at them. They also set fires on the street.

At one point, a protester tried to tackle a traffic police officer from behind before both sides rush in to the melee in the middle of a busy street, according to footage shown by local news channel Cable TV. Moments later, another officer appeared to fire two warning shots into the air.

APTOPIX Hong Kong Lunar New Year Protest

Rioters throw bricks at police amid lit fires on the streets in the Mongkok district. (Kin Cheung/The Associated Press)

The hawkers, long a common sight on Hong Kong's bustling streets, quickly attracted a strong social media following under the hashtag #FishballRevolution.

Hong Kong police said in a statement that the protesters had ignored their warnings to get off the street and shoved officers.

"To ensure public safety and public order, police took resolute actions, including using baton and pepper spray, to stop the unlawful violent acts," police said in a statement.

Hong Kong's Chief Executive Leung Chun-ying told reporters the perpetrators would be prosecuted. More than 80 officers and four reporters were hurt, he said.

"I believe the public can see for themselves from TV news reports the seriousness of the situation. The [Hong Kong] government strongly condemns such violent acts. The police will apprehend the mobs and bring them to justice," Leung said.

Acting District Commander Yau Siu-kei said 23 men and one woman were arrested on suspicion of assaulting and obstructing officers, resisting arrest and public disorder. The arrested were as young as 17 and as old as 70. Police said 48 officers were hurt by glass and flying objects.

Yau said two warning shots were fired.

The unrest started when authorities tried to prevent unlicensed street food sellers from operating on Monday night in Mong Kok, a working-class district of the city. The hawkers have become a local tradition during the Lunar New Year holiday but this year authorities tried to remove them.

The hawkers were backed by activists who objected to the crackdown over concerns that Hong Kong's local culture is disappearing as Beijing tightens its hold on the semiautonomous city.

The latest scuffles underscore how tensions remain unresolved more than a year after the end of pro-democracy protests that gripped the city. Mong Kok, a popular and densely populated shopping and entertainment district, was one of the neighbourhoods where activists occupied streets for about 11 weeks in late 2014, capturing world headlines with their demands for greater electoral freedom.

Hong Kong New Year Protest

A protester kicks a riot police in Mong Kok district of Hong Kong on Tuesday as Hong Kong's Lunar New Year celebration descended into chaotic scenes as protesters and police, who fired warning shots into the air, clashed over a street market selling fish balls and other local holiday delicacies, leaving dozens injured and arrested. (Kin Cheung/The Associated Press)

With files from Reuters