Google has begun alerting users whenever they click on a search result that may take them to a dangerous website.

The new feature, which had been spotted earlier this week, goes live officially Friday, according to an announcement from The Stop Badware Coalition, which is collaborating with Google on this effort.

When users attempt to click over to a site considered to be potentially dangerous, Google shows users an alert page that informs them of the possible risk and gives them the option to click back to the results page or continue on to the questionable site.

The flagged websites have been reported as dangerous to The Stop Badware Coalition. Google will progressively replace the generic alert page with pages containing specific reports about the sites. The Stop Badware Coalition will provide these individual reports as well.

The Stop Badware Coalition is a nonprofit organisation led by Harvard University and the University of Oxford and backed by Google, Lenovo Group and Sun Microsystems.

This new Google feature attempts to address a real problem: search engines routinely display links to sites that download spyware and adware to visitors' PCs, exploit security vulnerabilities, attempt to scam users, and include them in spam lists.

In the US, people land on malicious sites about 285 million times per month by clicking on search results from the five major search engines, according to a recent study conducted by McAfee Inc's SiteAdvisor unit.

Google didn't immediately reply to a request for comment.