HONG KONG (XINHUA) - Hong Kong, both a contributor to and beneficiary of the motherland's 40 years of reform and opening up, should uphold the original spirit of the "one country, two systems" principle and continue developing jointly with the country, the city's chief executive Carrie Lam said on Monday (Oct 1).

Mrs Lam made the remarks at the National Day reception held by the Hong Kong Special Administrative Region (HKSAR) government to celebrate the 69th anniversary of the founding of the People's Republic of China.

"The concept of 'one country, two systems' was advanced, first and foremost, to realise and uphold national unity... Today, as we celebrate the National Day, let us not forget the original spirit of 'one country, two systems' but bear in mind the mission of upholding our country's sovereignty, security and development interests," Mrs Lam said when addressing around 4,000 attendees, including members of the HKSAR executive and legislative councils, the consular corps, government officials, community group leaders and members of various community sectors.

Mrs Lam said this year's National Day celebration is particularly meaningful, as it coincided with the 40th anniversary of China's reform and opening up.

"Hong Kong has been playing the role of a contributor as well as a beneficiary in China's reform and opening up," she said. "In these 40 years, Hong Kong has been leveraging its advantages to serve the country's needs, developing jointly and sharing prosperity with the country."

As the country is entering a new historical era for further development, Hong Kong must keep reinforcing and enhancing its global competitiveness, said Mrs Lam. It must also proactively seize the opportunities arising from the Belt and Road Initiative and the development of the Guangdong-Hong Kong-Macau Greater Bay Area.

Hong Kong must also better integrate into the overall development of the country, Mrs Lam said, pointing out that the HKSAR government has been working with the strong support from the central government to create new areas of economic growth.

"For such work to flourish and bear fruit, as for a tree to grow tall and luxuriant, its roots must run deep and strong," she said, stressing that the roots lay in the upholding of the principle of "one country".