The Department of Justice said on Thursday that it has filed an appeal against the acquittal of one of the defendants in a subversion case relating to an opposition plot to take control of Legco to disrupt government operations.

Former district councillors Lawrence Lau and Lee Yue-shun were cleared of conspiring to commit subversion under the national security law last month, with three High Court judges saying in their verdict that they were not sure if the pair had intended to subvert state power.

The Department of Justice said it has filed an appeal against Lau's acquittal, but that it won't challenge the judgement regarding Lee.

Fourteen others were found guilty of the subversion offence and 31 pleaded guilty earlier.

Mitigation hearings for those convicted will begin later this month.