HONG KONG • Hong Kong is ill and needs medication, a mainland official based in the city has said.

Mr Wang Zhenmin, the legal head of the China Liaison Office in Hong Kong, also spoke of "heartbreak" caused by growing talk of independence which he ruled out for "1,000 years and forever".

Describing the city and the motherland as a unified body, he said Hong Kong had "caught a cold and got sick" and that both sides required medication, reported South China Morning Post.

"It is heartbreaking to see some people going for extreme means to destroy Hong Kong," said Mr Wang on Thursday at a luncheon hosted by the Asia-Pacific Law Association.

When asked if people should talk about self-determination or independence, he said "mission impossible - no way".

"(It's) not a real question. We should spend our time to discuss what are real questions. Don't waste time to discuss something impossible, even for a thousand years," he was quoted as saying by website Hong Kong Free Press.

Mr Wang said those advocating Hong Kong's separation from China were acting out of fear that the mainland's success was eclipsing the city's.

"Hong Kong's prosperity and stability are largely because of the motherland," he added. "Some people then think that now the motherland is developing well, Hong Kong will go downhill."

In response to accusations that his office had meddled in the recent legislative elections, he said it was normal for the central government in Beijing to care about Hong Kong's elections but his office had never acted outside the law.

Hong Kong, he added, should continue to serve as a role model for the country's economic and democratic development along with the rule of law.

"If the 7.3 million people in Hong Kong mess up democracy and bring only extremism, violence and separatism, how can the 1.4 billion people on the mainland pursue democracy without fear?

"In the future, we still hope Hong Kong can be a pioneer in democracy and rule of law," he said.

The former British colony was handed back to China in 1997 under a "one country, two systems" agreement that promised to maintain the global financial hub's freedoms and separate laws for at least 50 years.

A recent Chinese University of Hong Kong poll found that around one in six people now supports a separation from China after 2047.

Political commentator Johnny Lau told the Standard newspaper that he believed Mr Wang talked tough because Beijing had adjusted its strategy on Hong Kong after some localist lawmakers were elected to the legislature.

"Beijing is worried independence advocacy will spread with Legco as its platform, as well as about the convergence of Hong Kong independence and Taiwan independence," he said, referring to the Legislative Council (Legco).

"Beijing was ignorant that its feudalistic 'big brother' (position) was no longer effective and didn't realise Hong Kongers' demand for democracy."

In the Sept 4 Legco elections, Hong Kong residents voted into the council seven young lawmakers who espouse greater political freedom and a stronger identity for the city.

The Beijing government has warned the newly elected localist lawmakers, who will take office on Oct 1, against any talk of independence either "inside" or "outside" Legco.