A senior Beijing official has reiterated the central government's commitment to maintaining the "One Country, Two Systems" governing principle for Hong Kong, while urging the city to capitalise on its unique advantages.

Zheng Yanxiong, the director of Beijing's liaison office, on Friday described the territory's prosperity and stability as "rock solid", and said the rule of law, business environment, as well as democracy and freedom in the SAR, remain unchanged.

"Shortly after the signing of the Sino-British Joint Declaration 40 years ago, British-Hong Kong authorities unilaterally made changes to many of their promises. The last governor, Chris Patten, arbitrarily laid 'political landmines' for Hong Kong," Zheng told a Legislative Council luncheon.

"But the central government's commitment has never changed, and it has offered extreme care for Hong Kong.".

He also told lawmakers that the city has "risen from the ashes".

"The central government fully supports Hong Kong, and Hong Kong is rapidly advancing from stability to prosperity. The biggest change is that Hong Kong has transformed from a humiliating colony run by outsiders to the apple of the country's eye," Zheng said.

"Hong Kong serves as the bridge for the world to understand China, enter China, and shake hands with China... [Integrating into the country] will not marginalise Hong Kong, or even 'mainlandise' the city. Instead, it will further strengthen Hong Kong's status and advantages, and have better achievements."