A Hong Kong company run by members of the now-defunct opposition party Demosisto has been fined HK$10,000 (US$1,280) for breaking trade description laws over its stock of more than 900 boxes of face masks with false performance claims.

Customs officers raided the party’s registered address in San Po Kong and seized the masks, stored in yellow boxes printed with the declaration “Not made in China”, following complaints on May 22 last year.

At the time, the party, co-founded by opposition figure Joshua Wong Chi-fung, had slammed the operation and accused customs of political censorship through the Trade Descriptions Ordinance.

Officers dismissed the suggestion, saying they had been running the operation to ensure that common protective items available for sale in the market complied with the law.

Kwun Tong Court heard the masks were labelled with “ASTM Level 1” in product specification, the lowest grade – based on ratings of filtration and fluid resistance – in the certification by the global standards organisation ASTM International.

But a laboratory test revealed that the sample masks failed to attain the declared performance standard.

Prosecutors subsequently sought the expert opinion of Dr Simon Lam Ching, assistant professor of Polytechnic University’s School of Nursing, who said using such substandard masks in clinical settings would pose a “moderate” risk to health care professionals.

On Thursday, a representative of Chung Chi, a company run by Demosisto members which was supplying face masks to Kwun Tong restaurant Favilla, pleaded guilty to one summons of possessing goods with false trade descriptions for sale or manufacture.

Deputy magistrate Denise Tso Yin-chee fined the company HK$10,000 and confiscated all 935 boxes, containing 32,725 masks with an estimated market value of about HK$93,500.

Company director Isaac Cheng Ka-long, 21, the party’s then vice-chairman, did not show up in court to face a separate summons of possessing goods with false trade descriptions for sale.

Tobias Leung Yin-fung, 26, the company’s principal officer and the party’s then standing committee member, was also absent from court after being issued the same.

The pair will be served with fresh summons.

Meanwhile, Favilla and its director, Leung Pak-ho, were accused of supplying goods with false trade descriptions, over six boxes of the product.

Their case was adjourned until November 11.

Under the ordinance, any person who supplies goods with a false trade description in the course of business, or is in possession of any goods for sale with such misleading details , commits an offence.

Offenders face a maximum sentence of up to five years in prison and a HK$500,000 fine.