A webcam is positioned in front of YouTube's logo in Paris. [AFP]

A US congressional commission appealed Wednesday to YouTube to restore a Hong Kong pro-democracy anthem, saying blocking the video boosted authoritarianism and went beyond a local court order.

YouTube last month said it was complying with a Hong Kong court order and would block access to 32 videos of "Glory to Hong Kong," originally written for protesters who took to the streets in a failed 2019 movement to stop China's stifling of the city's autonomy.

In a letter to the CEOs of YouTube and its parent Google, the heads of the Congressional-Executive Commission on China, which looks at Beijing's rights record, accused the companies of improperly imposing a blanket ban on the song.

The order was targeting "seditious intent" through the song, including causing secessionist activities, but did not ban it for academic or journalistic activity, the lawmakers said.

"It is our opinion that the steps taken by your company thus far exceed what is required by the court's injunction and will have far-reaching implications for the free flow of news and information and the freedom of expression in Hong Kong," wrote Republican Representative Chris Smith and Democratic Senator Jeff Merkley.

"We would not want your company's actions to embolden the Hong Kong government in its increasingly growing authoritarian tendencies," they wrote.

The lawmakers also asked YouTube to clarify it will appeal the court ruling.

Responding to the letter, a YouTube spokesperson said that the company "shared the Commission's commitment to ensuring freedom of expression in Hong Kong."

"We strongly disagree with the Hong Kong High Court's order to block access to the listed videos for viewers within Hong Kong's borders," the spokesperson said.

"We pushed back against the government's demand that we remove these videos for over a year, and are continuing to investigate our options for an appeal."

YouTube says it is obliged to comply with court orders and only agrees to removal requests by governments after they come through a legal process.

The 32 videos remain accessible to users outside Hong Kong.

The United States has denounced the court order as the latest blow to the reputation of Hong Kong, a financial hub that was promised a separate legal and governance system when Britain returned it to China in 1997.

As Beijing has exerted more influence over the city, it has defended the curbs on the song as a "necessary measure" to safeguard national security.