This year, our country marks the 30th anniversary of the reform and opening-up process that has had a profound impact not just on China, but also on the rest of the world and Hong Kong.

On December 18, 1978, the Third Plenary Session of the 11th Central Committee of the Communist Party of China was convened in Beijing, which resolved to shift the focus of work to modernisation. Put simply, the long-held policy based on the principle of class struggle would give way to one that was geared towards economic construction.

This was a profound and historic decision. The reform and opening-up policy provided the Chinese people with an opportunity to innovate and give their best. Over the past 30 years, the Mainland has enjoyed rapid economic growth, with average annual GDP growth of 9.88%. Hundreds of millions of people have been lifted out of poverty. Living standards have improved significantly, which has laid a solid foundation for our country to make further progress.

The reform and opening-up has also brought China - home to one-fifth of the world's population - back into the international community and enabled it to contribute to global development.

In 1978, China's trade volume was less than 1% of the world total. Today, it accounts for about 8%. At the same time, China has been committed to maintaining peace and stability in the region and globally. In the future, China will continue to fulfill its international obligations as a world power promoting the welfare of mankind and working with other countries to build a harmonious world.

The Mainland's reform and opening-up, and the rapid development of Hong Kong, are closely intertwined. While the tremendous changes in our country have had an enormous impact on Hong Kong, Hong Kong has also been an active participant in the process and has made important contributions to our nation's development.

Earlier this year, I met Wang Yang after he assumed his post as Guangdong Party Committee Secretary. We discussed how to boost co-operation between Guangdong and Hong Kong. Mr Wang said Hong Kong had made valuable contributions to the development of Guangdong, as well as the reform and opening-up of our country.

The first wave of China's reform drive began in Guangdong, which made good use of Hong Kong's position as an international financial, trade and shipping centre to drive its economic development. As a result, Guangdong became a major engine of the country's reform.

Hong Kongers were the pioneers of investing in the Mainland. We were the first to establish joint ventures in the Mainland. Our business people were often sailing in uncharted waters. They experienced many difficulties and had to bear substantial risks.

Today, Hong Kong's realised direct investments in the Mainland have reached almost US$320 billion - about 40% of the Mainland's total external direct investment. In Guangdong alone, some US$112 billion has been invested - which is almost two-thirds of all direct external investment in the province. Hundreds of thousands of jobs have been created throughout the country by these investments.

Capital investment aside, Hong Kong has also exported management experience, international business networks and market economy concepts to the Mainland. This has helped our country to develop its own market mechanisms, and provided a useful reference for the ongoing economic reform.

Over the past 30 years, the Mainland has exported goods worth over US$1 trillion through Hong Kong - making Hong Kong the most important source of foreign- exchange income for our country.

Since the 1990s, increasing numbers of Mainland enterprises have raised funds through public listings in Hong Kong, which demonstrates the indispensable role that Hong Kong has played in the 'going out' process for Mainland enterprises. This has also strengthened Hong Kong's status as an international financial centre.

The contributions by Hong Kong entrepreneurs go far beyond their investments in the Mainland. Many have devoted their knowledge, expertise, time and personal wealth to promote the development of education and welfare in the Mainland. I believe their spirit of philanthropy has inspired similar endeavours by their Mainland counterparts.

Without doubt, Hong Kong has benefited greatly from the Mainland's reform and opening-up. In the early 1980s, rising land and labour costs put considerable pressure on our international competitiveness. The Mainland's reform and opening-up provided timely relief. Many local manufacturing companies moved to the Mainland, in particular the Pearl River Delta, to take full advantage of low production costs and thus enhance the competitiveness of their products.

At the same time, Hong Kong turned its focus to trade and financial services. Acting as an intermediary between China and the world, Hong Kong prospered from the Mainland's rapid economic growth and successfully transformed into one of the region's major business and financial services hub.

This transformation enabled Hong Kong - a developed economy - to sustain impressive average annual GDP growth of 5.7% to outpace the developed economies in Europe and America. Per capita income in Hong Kong rose from less than US$4,000 30 years ago to over US$30,000 today.

The role of Hong Kong will not diminish as our country continues to develop. Rather, our role will become more crucial.

First, Hong Kong will continue to play a vital role as the Mainland continues to enhance its economic structure and merge with the global economy. As an international trading port, services hub and innovation centre, Hong Kong can help the Mainland develop modern service industries including trading, logistics, convention and exhibition, information technology, accounting, legal and engineering services.

We can also help Mainland enterprises to fully utilise overseas markets to integrate into the world economy. There is much room to make use of our advantages in service industries, international networks and innovative capabilities to serve our country even better.

Second, almost every major economy has a world-class financial centre. Hong Kong is not only a fundraising centre for Mainland enterprises, it is also the only international financial centre in China.

The SAR Government has formulated strategies to strengthen Hong Kong's position as a financial centre and to provide better services for the Mainland. We will seek to encourage more public listings of Mainland enterprises in Hong Kong, expand our Renminbi business, promote asset management and develop the futures market.

Since financial services is one of our greatest strengths, there is much more we can do to help deepen the Mainland's financial reform, to further the opening-up of its financial market, and to enhance the efficiency of its fund raising.

Third, global competition today is among regional economies. By complementing each other's strengths, Hong Kong and Guangdong have set a successful example of regional co-operation over the past three decades. But there is still plenty more room for co-operation in the future.

We will strengthen co-operation with Shenzhen to build a world-class metropolis under 'One country, two systems'. We are also working with Guangdong on a wide range of fronts to transform the Pearl River Delta Region into a world-class economic zone, serving as the flagship for our country as it competes globally.

Fourth, our country's development requires good education and a vast pool of talent. Hong Kong has an excellent track record in attracting talent from around the world and in providing a high standard of tertiary education.

Over the past 30 years, Hong Kong has helped train thousands upon thousands of business, managerial and administrative professionals for the Mainland. Looking ahead, we can further extend our co-operation with the Mainland on education to produce more talent in different fields.

Lastly, given the strength of our legal system, market mechanisms, administrative efficiency, corporate governance, entrepreneurship and city administration, Hong Kong can help the Mainland to refine its market economic system, formulate effective public policies and strengthen its city administration, which will provide support for the country's rapid economic development in the future.

Although the world is in the grip of a financial turmoil and facing a recession, the co-operation between Hong Kong and the Mainland will not falter. The Central Government has pledged to back Hong Kong and take effective measures to support us. These measures will not only help Hong Kong face the present challenges, but also help with the continued opening up and reform of the Mainland.

In addition, the 4 trillion yuan stimulus plan recently unveiled by the Central Government will not only help sustain the Mainland's economic growth, it will also provide a plethora of business opportunities for Hong Kong enterprises.

Hong Kong and Guangdong will continue to deepen co-operation in the financial and services sectors, as well as cross-boundary infrastructure, in order to maximise our regional advantages as we tackle the economic crisis together.

The past 30 years of reform and opening-up have been of singular importance to China, and the world. Not only has it changed the course of our nation's history, it has also impacted on the economic development of the whole world.

Hong Kong should take great pride in its active and unique role in this process. As the reform and opening up continues, we will grasp every opportunity to deepen our integration with the Mainland, and make the best use of our competitive strengths to contribute to the development of our country.

At the same time, Hong Kong will enter a new phase of development that holds even greater promise for our city and our people.

This piece by Chief Executive Donald Tsang on the 30th anniversary of China's reform and opening up was published in several Hong Kong newspapers.