Hong Kong's High Court on Friday rejected a government bid to ban the protest song "Glory to Hong Kong", saying it could undermine freedom of expression and cause potential "chilling effects".

The government's application for an injunction came after "Glory to Hong Kong" was played mistakenly at several international sporting events, including rugby and ice hockey competitions, instead of China's national anthem "March of the Volunteers".

China-ruled Hong Kong does not have its own anthem but as a Chinese territory since its return from British rule in 1997, it uses China's anthem.

The protest song was widely sung and played during the city's pro-democracy protests in 2019. It was later deemed unlawful after China imposed a national security law on the financial hub as part of a crackdown on dissent.

In a written judgement rejecting the injunction, High Court Judge Anthony Chan wrote: "The court recognized the engagement of the right to freedom of expression in the consideration of this application", while noting "chilling effects" that might be generated if the injunction was granted.

"It is by no means over-stretched to envisage that perfectly innocent people would distance themselves from what may be lawful acts involving the song for fear of trespassing the injunction which has severe consequences," Chan added.

"I cannot be satisfied that it is just and convenient to grant the injunction. This application is accordingly dismissed."

When the government first applied to the court for a total ban of the song in June, the song was soon taken down from several online music streaming platforms including iTunes and Spotify.

Hong Kong officials had also criticized Google for refusing to change its search results to display China's national anthem instead of "Glory to Hong Kong" when users searched for Hong Kong's national anthem.

A senior Hong Kong official, Sun Dong, said earlier this month that Google had told the government to first prove that the song violated local laws - thus prompting the legal application.

Google parent Alphabet gave no immediate response to a Reuters request for comment on the judgement. It was not immediately clear whether authorities would appeal the decision.

The Hong Kong Journalists Association (HKJA) that had opposed the government injunction bid, welcomed the decision.

"Exercising public power would create a chilling effect, threatening innocent people," HKJA head Ronson Chan told reporters outside the court. "I think the judgement is very reasonable."

The intention is to restrain anyone from broadcasting, performing, printing, publishing, selling or offering for sale, distributing, disseminating, displaying or reproducing the song in any way including on the internet.

The injunction would identify anyone who defies the restraints as inciting others to separate Hong Kong from China - a seditious act besides insulting the national anthem.

It would also be illegal to assist or allow others in any of the stipulated acts, according to the writ filed by Justice Secretary Paul Lam Ting-kwok.

The injunction covers too 32 YouTube videos related to the song, including instrumental clips and versions in different languages, as well as adaptations, melodies and lyrics that are "substantially the same" as the song.

"Glory to Hong Kong" was composed in 2019 when the city was convulsed by months-long protests that drew millions of people against tightening Chinese control of the freewheeling city.

(Staff and agencies)

High Court rejects govt bid to ban protest song ‘Glory to Hong Kong’