HONG KONG - Two opposition lawmakers who are vocal critics of Beijing and the Hong Kong government are among the 16 arrested by the police for suspected involvement in last year's unrest.

Lawmakers and Democratic Party members Ted Hui and Lam Cheuk Ting were picked up from their homes at around 6am on Wednesday (Aug 26), the party announced via social media accounts.

Police on Wednesday said they arrested 16 people aged between 26 and 48.

Four of the arrests - Hui, Lam, a male chef and a female social worker - are linked to a protest outside Tuen Mun police station on July 6 last year, where they face charges ranging from conspiring with others to damage property, joining an illegal assembly and obstructing justice.

In a statement, Hui, who is a familiar face at last year's demonstrations, said he was only mediating at the scene in Tuen Mun.

Thirteen of the arrests, including that of a vice-president of a bank, receptionist and driver, are linked to the high-profile Yuen Long clashes on July 21 last year. Some of those detained have ties to triads, the police said.

That night, a group of white-clad men armed with sticks and clubs attacked black-clad passengers at Yuen Long station, resulting in several dozens injured, including Lam, who is accused of rioting that night.

The men in white were reported to be from triads and were beating up the group in black, believed to be passers-by and protesters on their way home after an anti-extradition demonstration.

Lam, who was at the scene, had suffered injuries to the mouth, hands, feet and abdomen.

He told the media after the incident that he went to the MTR station after hearing about the attack.

Lam said he called Yuen Long Police District and asked for officers to be sent to the scene urgently but there was no action from the police for more than an hour after he contacted them.

The police were slammed for what was seen as their delayed response, with officers arriving at the scene nearly 40 minutes after the attack began, and fuelling rumours of collusion with those behind the violence.

Yuen Long is part of the New Territories, a largely rural area close to the Chinese border where a number of villagers are known to have ties to triads and are supportive of the pro-Beijing establishment.

Hong Kong's then police chief Stephen Lo later defended his officers, saying there was a need to redeploy manpower from other districts, as police and protesters at that time had been locked in pitched street battles in the Sheung Wan district some 30km away.

The incident marked a turning point in the demonstrations as protesters started to direct their anger at the police, and trust in the city's officers, billed as Asia's top in the past, nose dived.

On Wednesday, the police said that as of Tuesday, a total of 44 people aged between 18 and 61 have been arrested over links to the July 21 incident.

As at Aug 20, seven have been charged with participating in riot and conspiracy to wound with intent.

In a joint statement on Wednesday, 20 pan-democratic lawmakers accused law enforcers of insulting and intimidating people's representatives, adding that the move indicates that the government has no intention of addressing allegations of police brutality during last year's protests.

But pro-Beijing lawmaker Junius Ho, who was filmed shaking hands with white-clad men in Yuen Long on the night of the attacks, applauded the arrests on Wednesday, saying "being late is better than never".

Mr Ho, who denied involvement in the attacks, said the arrests will restore order in Hong Kong.

The unrest last year that spanned more than half a year was sparked by Chief Executive Carrie Lam's push for an extradition Bill that would have suspects sent to the mainland. The protests morphed into an anti-government movement that gained momentum following the Yuen Long attacks and other incidents.

The latest round of arrests comes two weeks after the high profile arrest of media tycoon Jimmy Lai and his two sons, who were among seven men detained under the national security law.

It also follows the late July disqualification from the now-postponed Legislative Council election of 12 opposition candidates, including activist Joshua Wong and the Civic Party's Dennis Kwok, Kwok Ka Ki and Alvin Yeung, many of whom oppose the security law.