A Hong Kong court has issued an arrest warrant for the former vice-chairman of disbanded opposition party Demosisto for skipping criminal proceedings in connection with a stock of more than 900 boxes of surgical masks said to have had false performance claims made for them.

The move came after Issac Cheng Ka-long was served with a summons after prosecutors said he had breached trade description laws by possessing for sale substandard masks, which were contained in yellow boxes printed with “Not made in China”.

The 22-year-old has been absent from the proceedings since the case was first referred to Kwun Tong Court last September.

He revealed on Facebook in April he had moved to Britain before the first hearing.

A box of the face masks at the centre of allegations of false claims over their efficiency.

Deputy Magistrate Tobias Cheng Yun-chung granted a request by prosecutors on Friday for an arrest warrant after he accepted the appropriate legal documents had been served on the activist.

The deputy magistrate issued a separate warrant for the arrest of Tobias Leung Yin-fung, 27, a former standing committee member of Demosisto, who received a summons for the same offence.

But he said the pair would still be released on a HK$10,000 bond after they had appeared in court.

Customs officers raided the former party’s registered address in San Po Kong on May 22, 2020 following complaints and seized the masks.

The party, co-founded by jailed opposition activist Joshua Wong Chi-fung, disbanded just hours before the national security law, which bans acts of secession, subversion, terrorism and collusion with foreign forces, came into force on June 30, 2020.

The group had slammed the raid operation and accused customs officials of political censorship using the Trade Descriptions Ordinance.

But customs officers insisted their aim was to ensure that protective items destined for the public complied with the law.

Prosecutors have alleged the masks falsely claimed to have at least 95 per cent efficiency in filtering bacteria and submicron particles, which would pose a moderate risk to health professionals if they used them in clinical settings.

No charges have been laid in connection with the declaration on the boxes.

The trade description offences are punishable by up to five years in prison and a HK$500,000 fine on conviction.