China's deep sea research submersible Jiaolong is making its first-ever visit to Hong Kong, on its return from a mission in the western Pacific.

Students and officials on Tuesday had tours of Jiaolong and its mothership, Shenhai Yihao, during a three-day port call at Tsim Sha Tsui's Ocean Terminal.

Deputy Chief Secretary Warner Cheuk said the vessels are an important part of China's participation in a project it leads on digital deep-sea typical habitats, under the United Nations' Decade of Ocean Science for Sustainable Development scheme.

He said their visit to the SAR fully demonstrates the central government's care and support for Hong Kong.

"I hope different sectors of the Hong Kong community will seize this opportunity to learn a lot more about the development of marine science," he said at a welcome ceremony.

"I also hope that this event can inspire more young Hongkongers to devote themselves to deep-sea research, and actively take part in the international deep-sea science project."

The director-general of the Deep Ocean Affairs Administration, Wu Changbin, said the mission involved scientists from five different continents.

He said it was an operation where China and different countries jointly sought development in exploring the deep sea and sharing results.

The head of the Hong Kong University of Science and Technology, Nancy Ip, said the institution was honoured to take part in the UN project by coordinating and organising the team of scientists.