Commerce secretary Algernon Yau said on Sunday Hong Kong will surely become a main business partner with Cambodia, as they create more opportunities in the region, on the mainland and the Greater Bay Area.

The minister said Hong Kong is ready for greater co-operation as the SAR is more integrated in China's strategic development, including the bay area and the Belt and Road initiatives.

He cited many factors for the partnership, such as Hong Kong's free economy, simple and low tax system, infrastructure network, market-led international business environment and the territory's free trade agreement with the Association of Southeast Asian Nations (ASEAN) countries.

Yau made the comments during a speech in Phnom Penh to celebrate the 25th anniversary of the handover.

"Under the strong support of the Central People's Government and the One Country, Two Systems principle, Hong Kong has developed into a world class city in Asia in the past 25 years," Yau said, as he concluded his trip to promote the advantages and business opportunities of the SAR.

He said Hong Kong will grasp "unprecedented opportunities" together with regional partners, including Cambodia.

More than 400 people were at the lunch, including the Chinese Ambassador to Cambodia, Wang Wentian, and local officials.

During his four-day trip to Cambodia, Yau held talks with his ASEAN counterparts to shore up support for Hong Kong's bid to join the Regional Comprehensive Economic Partnership free trade agreement.