Hui had been facing criminal charges in several cases at the time, including perverting the course of justice, access to a computer with dishonest intent, and alleged criminal damage.
“The deception was carefully orchestrated by the respondent (Hui) with the consequences that public confidence in the administration of justice had been greatly undermined,” wrote Chan, who had found Hui guilty on four counts of contempt of court in June.
Hui was among dozens of democrats who took part in an unofficial primary election in August 2020, that was later deemed illegal by authorities. Forty-seven of these democrats were arrested in early 2021 for alleged conspiracy to commit subversion that could see them jailed for life.
Legal proceedings are ongoing, with many of the democrats detained and denied bail ahead of the trial.
In a social media post on Thursday, Hui described the sentence and criminal proceedings against him as “contemptible”.
“After the National Security Law came into effect in Hong Kong, the courts in Hong Kong have been reduced to become courts of the (Chinese) Communist Party. Political trials, and sentencing against dissent has become the norm in Hong Kong,” Hui wrote.
More than 200 people have been arrested for alleged violations of the national security law since 2020.
Hong Kong and Chinese authorities say the national security law has restored stability to Hong Kong after mass pro-democracy protests in 2019, and that the judiciary remains independent.