China's top court issued a guideline on Tuesday aimed at severely punishing those who disturb judicial work or take revenge on legal officers, after a grassroots judge was killed by one of his litigants at the end of last month.

The guideline stipulates that those found guilty of interfering in judicial affairs, including threatening, insulting or harming judges, will face severe punishment, to ensure justice is served and to protect the safety of judges.

On Jan 26, the day before the Spring Festival, Fu Mingsheng, a retired judge from a court in Luchuan county, the Guangxi Zhuang autonomous region, was stabbed to death in his home by the defendant in a divorce case Fu handled in 1994.

Long Jiancai, 67, the attacker, has been detained on suspicion of homicide.

Fu, 63, began working as a judge on domestic dispute cases at the county court in 1978, retiring in November 2013.

After a preliminary investigation, the Supreme People's Court said on its micro blog on Monday that Long's motivation was his dissatisfaction with the verdict given by Fu in 1994.

"The suspect's actions touched the legal bottom line and disturbed public order. No matter how discontent he is with the judgment, he has no right to harm the safety of others," the top court said.

"If judges, the last line of defense against injustice, have their safety put in danger, how can they protect litigants' rights and push forward the rule of law?" it added.

The China Judge Association said on Monday that Long's actions must be criticized and penalized, "as it threatens the authority of courts and judicial credibility".

"Danger posed to judges threatens the rule of law, and damages public order and social stability," it said.

Guo Jie, a judge from Fujian province who specializes in cases involving divorces and children's disputes, described Fu's death as shocking, adding that the case reminded her of another tragedy in Beijing last year in which former judge Ma Caiyun, 38, was shot in the stomach and face at home. She was taken to hospital, but died.

One of the suspects was a litigant who was discontent with the division of property in a divorce verdict given by Ma.

"I feel increasingly unsafe, especially outside of my working environment," Guo said.

Although the government issued a rule to ensure judges' safety in July, aiming to severely punish those taking revenge on judicial officers, "no severe punishments have been announced publicly," which is why lots of judges remain anxious, according to Guo.

"A safe environment is crucial for us to properly handle cases," she added.