The Guangdong-Hong Kong-Macao Greater Bay Area is showing robust demand for more diversified and in-depth cross-border financial services and products, said a survey led by a unit of the People's Bank of China, the central bank.

New demand is booming in a wide range of investment categories and institutions, hinting that the nation's financial opening has entered "uncharted waters," economic experts said.

"As the Greater Bay Area is at the forefront of China's financial reform and opening-up, the survey provides a sound foundation for formulating precise and innovative plans on specific sectors and segments," said Guan Tao, global chief economist at BOC International, a unit of Bank of China.

The Financial Society of Shenzhen Special Economic Zone, a research institute led by the Shenzhen Central Sub-branch of the PBOC, published a report on Aug 28 based on a survey of more than 20,000 people and about 700 representative firms across the border.

Its data showed the three most popular Hong Kong investment tools for Guangdong residents are funding, insurance and stock products. With the expansion of cross-border stock and bond channels, more than half the people in the area foresee enlarging their stock investment targets.

Manifold personal asset allocation services in Hong Kong, an international financial center, bode well for Guangdong residents, so it is necessary for the Special Administrative Region to accelerate the expansion of mainland individual investment channels, said Pan Hongsheng, chief economist at the China Institute of Finance and Capital Markets.

Meanwhile, the percentages of Hong Kong and Macao residents who long for cross-border payment and investment services are at 49.5 percent and 37.1 percent, respectively.

But Pan pointed out their demand for mainland investment is still concentrated on general deposits, wealth management products and the stock market.

Mainland banks have a huge potential to grow in providing more financial services for individuals in the two SARs, he added.

He said scores for China's financial opening progress marked by securities and futures institutions are "obviously" lower than those of banks because existing financial opening pilot policies are mostly kept within banking and insurance services.

Securities and futures institutions have expressed expectations to involve more stocks in cross-border stock connects and open a wider service range.

Pan said China's financial opening-up has entered "unchartered waters" and should steadily strengthen the two-way exchange of more financial markets, institutions, businesses and products.

The cross-border usage of renminbi in the area also injected new impetus to the internationalization of the currency, especially the digital RMB or e-CNY.

More than three-quarters of surveyed companies in the Greater Bay Area believe that the RMB should be promoted as the main currency in Shenzhen, Guangdong province, and Hong Kong capital exchanges.

More than one-third of surveyed Hong Kong residents believe that digital RMB can improve the efficiency and security of transactions, indicating the potential for cross-border usage of the digital currency.

The innovative payment method is thriving in Shenzhen. The city had opened the largest number of digital RMB wallets in China by the end of July, the Shenzhen Central Sub-branch of the PBOC said.

Wu Ge, chief economist at Changjiang Securities, said it is obvious that demand for cross-border financial services is "strong," but he added opening-up should be carried out in a planned manner and under the premise of maintaining the basic stability of the domestic market.