Hong Kong websites are the most likely to hit visitors with unwanted ads, viruses and spam, research from an internet security company has found.

More than 19 per cent of websites using the ".hk" domain name pose a security threat to visitors, the research by United States software firm McAfee found.

China-based sites are the second most risky with 11 per cent, while those from Finland and Japan are the two safest. Romanian and Russian sites were also a threat to web users.

Last year, the survey ranked Hong Kong as only the 28th most risky internet location.

"Just like the real world, the virtual threats and risks are constantly changing. As our research shows, websites that are safe today can be dangerous tomorrow," said Jeff Green, senior vice president at McAfee.

"Surfing the web based on conventional wisdom is not enough to avoid risk online."

The study looked at 9.9 million well-visited websites in 265 countries and ranked them by the amount of adware, spyware, viruses, spam, excessive pop-ups, browser exploits or links to other problem sites.

The generic domain name ".info" was considered the most problematic, the survey found, while ".gov" was the safest.

Hong Kong and China are often cited as the source of much of the world's spam - unwanted email messages that fill computer users' inboxes.

AFP