HONG KONG (BLOOMBERG) - A Hong Kong appeals court rejected the government's request to temporarily extend a controversial mask ban, despite China's criticism of a lower court decision declaring the measure unconstitutional last month.

The government failed to convince the Court of Appeal of the need to reinstate the ban against protesters wearing masks before hearings on the case proceed next month, Justices Jeremy Poon and Johnson Lam wrote in a decision handed down on Tuesday (Dec 10).

The judges said that the ruling should not be seen as indicating the result of the appeal, which will be heard Jan 9-10.

The decision represents another setback for Chief Executive Carrie Lam, who instituted the unprecedented mask ban in October by invoking an emergency law for the first time in more than a half century.

A lower court voided the mask measure on Nov 18, saying it "exceeds what is reasonably necessary to achieve the aim of law enforcement, investigation and prosecution of violent protesters".

A Chinese parliamentary committee that oversees the laws of the former British colony denounced the earlier decision, saying it "seriously weakened" the power of Hong Kong's Chief Executive to maintain law and order. Mr Zang Tiewei, a spokesman for the legislative affairs commission of the National People's Congress, said Parliament was the only body with the authority to interpret Hong Kong law - a claim disputed by the Hong Kong Bar Association.

The criticism raised the spectre of Beijing's direct intervention in a judicial system whose independence is often seen as a key competitive advantage of the global financial centre. The sweeping Emergency Regulations Ordinance used to institute the mask ban has been seen as a key tool for Mrs Lam to manage the sometimes violent pro-democracy protests that have gripped the city for the past six months.

Police had arrested hundreds over alleged violations of the regulation, which called for jail sentences of up to one year for violators. Some protesters deliberately flouted the ban by wearing masks and costumes at rallies.