Google is asking everyday Web surfers to help with its efforts to stamp out malicious Web sites.

The company has created an online form designed to make it easy for people to report sites they suspect of hosting malicious code. It's the latest step by Google to expand its database of the bad Web sites it knows about, as those sites continue to proliferate.

"Currently, we know of hundreds of thousands of Web sites that attempt to infect people's computers with malware. Unfortunately, we also know that there are more malware sites out there," Google's Ian Fette wrote in the company's security blog.

The simple form has an entry box for the Web site's URL and a space to provide additional information. Users also fill out a "captcha" to prevent software robots from reporting sites automatically.

Google displays a warning in its search results if it believes a Web site is malicious. But earlier this week researchers noted that some Google searches for relatively mundane topics were producing results loaded with malicious sites, apparently the result of a campaign by hackers.

Security vendor Sunbelt Softwaresaidhackers appeared to be using various tricks to ensure their malicious sites appear high in Google's search results. Sunbelt said it turned up 27 different domains hosting malware, each with up to 1,499 malicious pages, or some 40,000 pages in total.

Two days later the sites disappeared from the results, although Google would not say if it cleaned them out.