HONG KONG • The Hong Kong government will try to enact a law penalising people who boo the Chinese national anthem "as soon as possible", an official said yesterday, in a move that critics say undermines the Chinese-ruled city's autonomy and freedoms.

In the past few years, some Hong Kong football fans have booed the national anthem during World Cup qualifiers and other matches.

The Asian Football Confederation warned the Hong Kong Football Association on Tuesday over the conduct of fans who booed the Chinese national anthem during a match last month.

China has passed a law stating that disrespecting the anthem could result in imprisonment. The law has come into force in China but has yet to be extended to Hong Kong.

Hong Kong Secretary for Constitutional and Mainland Affairs Patrick Nip said the city had a constitutional obligation to follow up on the move by China's Parliament.

He said the law will now be added to the annex of Hong Kong's mini-Constitution, the Basic Law, and put to the city's 70-strong legislature. "We will do it as soon as possible," Mr Nip told lawmakers, adding that there would be a consultation process.

Hong Kong is a former British colony that returned to Chinese rule in 1997 under a so-called "one country, two systems" formula that promises a high degree of autonomy, including an independent judiciary. But China's growing reach into Hong Kong's affairs has stoked tensions and mass protests, including the 2014 "Occupy" civil disobedience movement.

Mr Nip said no decision had been made on jail terms, but the government would make reference to existing laws concerning the desecration of China's national flag, an offence which carries a maximum sentence of three years.

Some critics said the move was another instance of China's tightening iron grip. "If a country (China) wasn't using totalitarian and autocratic ways to make people feel under pressure, I believe many more Hong Kong people would respect the national anthem," said Mr Dennis Kwok, a lawmaker with the Civic Party.

The Chinese authorities have strived to instil greater patriotism in Hong Kong while condemning a push from democracy activists to distance Hong Kong from Beijing.

"In recent years, incidents of disrespecting the national anthem have occurred in Hong Kong, challenging the bottom line... and triggering rage," said Mr Zhang Rongshun, who leads a legislative affairs commission of China's Parliament, the National People's Congress, according to Xinhua news agency.

"It is urgent and important to apply the National Anthem Law in Hong Kong in a bid to prevent and handle such offences," he added.

REUTERS