Hong Kong billionaire tycoon Li Ka-shing says if Britain votes to leave the European Union, his company will invest less in the country.

Li, one of Asia's richest people, spoke at a news conference following the release of annual results for his conglomerate, CK Hutchison Holdings.

Britain is preparing for a June 23 referendum on whether to remain in the 28-nation EU amid a heated debate about its role in the bloc.

Li's British business interests include investments in ports, retail, infrastructure and mobile phones.

The tycoon said he's confident that the campaign to get Britain to exit "won't be successful."

However, he added that if Britain decides to leave, his company's investment level there will "of course" be lower, although he did not offer any specifics.