HONG KONG (AFP) - A Hong Kong TV station has been flooded with complaints after it subtitled a programme in a Chinese script associated with the mainland, reflecting deep-seated fears that Beijing is eroding the city's identity.

Hong Kong uses a different version of Chinese script and is fiercely defensive over both its written and spoken language.

The city uses traditional Chinese, a more complex set of characters, whereas simplified Chinese is more popular across the border.

The vast majority of Hong Kong residents also speak Cantonese as their first language, not Mandarin as on the mainland.

Language has become an increasingly sensitive issue as concern grows that Beijing is trying to stamp out local culture in the semi-autonomous city.

There are fears Cantonese is being sidelined in schools to make way for Mandarin under pressure from the authorities.

On Monday (Feb 22), local news channel TVB used simplified Chinese in subtitles to a Mandarin news programme, triggering a flood of complaints.

"As of the end of yesterday, the latest complaint figure was over 13,000," a spokesman for the Office of the Communications Authority told AFP Thursday (Feb 25), with no detail immediately available on the nature of the complaints.

TVB defended the move, saying it would "better serve different audience needs" and said simplified Chinese would be used in subtitles for only its Mandarin newscasts, not its Cantonese newscasts.

Critics laid into the pro-establishment channel, already unpopular with the city's youth and pro-democracy advocates who dub it "CCTVB", a pun on the official Chinese broadcaster CCTV.

"Simplified characters are only viewed and written by the illiterate,", said one comment on the Apple Daily website.

"TVB indeed seemed to have done something unnecessary or even stupid," said another on the South China Morning Post's site.

Simplified Chinese has gained precedence on the mainland since a controversial language reform introduced by the Communist party in the 1950s to promote literacy.

The head of Hong Kong's legislature Jasper Tsang on Thursday (Feb 25) said China should revise its policy on simplified characters, arguing traditional characters were easier to identify.

The battle to preserve Hong Kong's language was also one of the threads running through recent local box office hit Ten Years, a dystopian depiction of how the city could look in a decade's time.

Comprised of five short films, one portrays a taxi driver who speaks only Cantonese and struggles to communicate with irate passengers who want to speak Mandarin.

Fears that Hong Kong's identity and freedoms are gradually disappearing are infecting a range of areas, from education and the arts to politics and the media.

The disappearance of five Hong Kong booksellers known for publishing titles critical of the Chinese government has stoked tensions.

Four of the men are under criminal investigation on the mainland and the fifth has said he is "assisting" authorities there.

Frustrations among some young protesters boiled over earlier this month when they clashed with police, leaving more than 100 injured.