The Shenzhen-Hong Kong-Guangzhou cluster has overtaken its Tokyo-Yokohama rival to claim the top spot in the Global Innovation Index (GII), moving up from second place last year.

The index, by the World Intellectual Property Organisation, measures the amount of innovation activity in a cluster, with criteria including international patent filings, scientific publications and newly added metric, venture capital deals.

Chief economist at the organisation Carsten Fink said the Shenzhen-Hong Kong-Guangzhou cluster is particularly strong when it comes to venture capital deals, and there is a more vibrant capital scene for funding start-ups compared to Tokyo-Yokohama.

He said the cities in the Chinese cluster are able to cross-fertilise and collaborate.

"Hong Kong is particularly well-known for its excellent scientific institutions and its universities, a lot of the patenting that emerges out of company research development activities originates from companies in Shenzhen," Fink said.

"There are many examples of scientific projects in Hong Kong that led to start-up creations in Shenzhen."

Fink said policymakers in Hong Kong should continue doing what they are doing, adding that artificial intelligence is an important area that needs investment.

"It is of course important to stay at the cutting-edge, to adapt to continuous technological progress."

A GII report on individual cities will be unveiled on September 16.