Google has posted an official statement, on its company blog, as to why users were redirected to a warning page for every site they tried to visit for almost an hour on Saturday afternoon.

"If you did a Google search between 6:30 a.m. PST and 7:25 a.m. PST this morning, you likely saw that the message "This site may harm your computer" accompanied each and every search result. This was clearly an error, and we are very sorry for the inconvenience caused to our users", the company said in a statement on its official blog.

The errors, which meant Google listed every site in its database as a potential threat, occurred due to simple human error according to the search giant.

Google says it flags search results with the message "This site may harm your computer" if the site is known to install malicious software in the background or otherwise surreptitiously. However, when engineers performed what was supposed to be a routine database update an error meant that all sites where labelled as harmful, causing chaos to millions of internet users.

"Unfortunately (and here's the human error), the URL of '/' was mistakenly checked in as a value to the file and '/' expands to all URLs", explained Google as to how it internally marks rouge sites.

Google finished the blog post with an apology to searchers and "site owners" whose pages were incorrectly labelled".

It has said it will investigate the incident and put more robust file checks in place to prevent it from happening again.