Hong Kong's legal sector has strongly condemned death threats against three judges who convicted the special administrative region's first defendant under the National Security Law.

Experts said such threats seriously challenged the rule of law and judicial independence in Hong Kong, and urged more protection for judges.

After the High Court judges found a motorcyclist who rode into police guilty of terrorism and incitement to secession on Tuesday, Judge Esther Toh Lye-ping received a phone call that threatened to launch a bomb attack against her and slash the other two judges with knives.

Police categorized it as a criminal threat and the case is being investigated by the Organized Crime and Triad Bureau.

Hong Kong's Department of Justice said in a statement issued on Tuesday night that criminal intimidation of judges is "unacceptable" and constitutes a serious offense.

Under section 24 of the Crimes Ordinance, anyone convicted of threatening another person with injury could face up to five years in prison.

Separately, a spokesperson for the judiciary said that any attempt to impose undue pressure on judges should be severely condemned, as judges and judicial personnel are fulfilling their legal duties in accordance with the law and upholding the rule of law in a spirit of impartiality and selflessness.

Barrister and lawmaker Priscilla Leung Mei-fun said that no one should undermine justice by insulting or threatening judges. Dissatisfaction toward a judicial decision must be conveyed through appropriate and lawful means, she said.

She said Hong Kong people's respect for the rule of law had declined since the Occupy Central movement in 2014, when Benny Tai Yiu-ting took the lead to pursue political goals through unlawful means.

The consequences were seen in the social unrest of 2019, during which a wide range of residents, even teenagers, engaged in reckless acts that disregarded the law.

Noting that laws are the most civilized solution to social disputes, she called on Hong Kong people to cherish and respect the current legal system.

Barrister Lawrence Ma Yan-kwok cautioned that such threats to judges' safety may impair the impartiality of trials and affect the city's judicial independence.

He said Hong Kong has witnessed an intensification of threats and insults toward judges in recent years. Law enforcement agencies should take such behavior seriously and strengthen the protection of judges.

On May 28, after District Court Judge Amanda Woodcock sentenced eight defendants who organized and participated in an illegal assembly in 2019 to prison, the judge's office received at least three calls that contained insulting and threatening remarks.

On Dec 3, So Wai-tak, chief magistrate of the West Kowloon Magistrates' Court, who was designated to hear National Security Law trials, received a menacing phone call that threatened to kill his family. So reported the call to the police.

Expressing concerns that such hostility toward judges may escalate, Ma suggested the authorities arrange personal bodyguards for judges handling politically sensitive cases, such as those related to the National Security Law.

The Small and Medium Law Firms Association, whose membership includes 1,000 legal practitioners in Hong Kong, said such intimidation challenged the bottom line of the rule of law and hurt the fundamental interests of Hong Kong people.