The controversy began as links to the pro-democracy song Glory to Hong Kong appeared ahead of the national anthem "March of the Volunteers" tune when people searched for the city's national anthem.

The protest song was accidentally played for Hong Kong athletes at two international sporting events last month, prompting the city to demand it be lowered down in the list of search results.

"Google handles billions of search queries every day, so we build ranking systems to automatically surface relevant, high quality and helpful information," the tech giant in response to the request.

"We do not manually manipulate organic web listings to determine the ranking of a specific page."

Hong Kong's security chief Chris Tang Ping-keung said the company's explanation was "evasive" and "inconceivable."

Chief Executive John Lee Ka-chiu has said Google has a "moral obligation" to respect a country's anthem, while the foreign ministry said internet companies "have a duty to deliver correct information to the public."

Google said it was in contact with the city's government to explain "how [its] platforms and removal policies work."

On information accuracy, Lee said the Chinese press should continue its function of spreading facts and providing quality news to the public.

He added that there are many false news stories among the overwhelming amount of information online and that the media should uphold journalistic integrity to clarify facts.

"No responsible and ethical media worker would accept a reporting of false information, let alone putting it in headlines [which could be widely circulated]," he said.

He also said that journalists must uphold the spirit of objectivity and impartiality - and keep a distance from fake journalists - in order to ensure the continued prosperity of the industry.