The wealthy sultanate of Brunei on the north coast of the island of Borneo has been struggling to attract foreign direct investment as the supply of oil and gas that made it rich starts to dwindle. So the advent of the Belt and Road Initiative and China's increasing interest in the country couldn't have come at a better time. The state visit by China's president Xi Jinping in November will have helped raise Brunei's profile among Chinese investors. But as Rian Maelzer reports from the Brunei capital, Bandar Seri Begawan, Chinese money has already been flowing into an array of projects and industries.

This sprawling petrochemical and refinery complex being built by the Hengyi Group on an island just off Brunei's coast is China's flagship investment here. With the cost of the first phase alone estimated at $3.5 billion, it's the country's largest-ever foreign investment. Across this sultanate, Chinese companies are investing in infrastructure and logistics, finance, education, aquaculture, heavy industries and there's no doubting what spurred this rapid growth.

RIAN MAELZER BANDAR SERI BEGAWAN, BRUNEI "The Belt and Road Initiative has greatly raised awareness of and interest in Brunei among Chinese businesses and investors."

China's Guangxi Beibu Group has formed a joint venture to manage, expand and modernize Brunei's container port, and build an integrated industrial park.

LI ZONGZE, DIRECTOR MUARA PORT COMPANY "Brunei provides us a stable and safe investment environment. With the improvement of the service and efficiency of Maura port, we hope to cut the logistics cost for Brunei and attract more foreign investment to Brunei."

Bank of China opened here in 2016.

WANG XIAOLIN, GM BANK OF CHINA, BRUNEI BRANCH "We are becoming increasingly important as more and more Chinese companies are investing in Brunei. When we were coming in, Western banks like Citibank and HSBC were withdrawing. We have brought new confidence to this market."

With Brunei to struggling to attract foreign investment, especially in manufacturing, China's growing interest has been a welcome tonic. HLDS produces steel pipes.

GAO WENGE, VICE-GM HLDS STEEL "We have techniques and management experience to share. As we speaking, our products are being sent to all over the world. Our plan is to produce 10 thousand tons of world-class quality steel pipes at a per year for the industries like oil and natural gas, and construction."

And following President Xi Jinping's state visit to Brunei last month, it's likely that even more Chinese firms will be keen to see what opportunities the sultanate can offer. Rian Maelzer, CGTN, Brunei.