According to a website dedicated to tracking which sites have been blocked or censored by the Chinese government, Google.com along with a host of other Google services are no longer accessible from mainland China.

China Blocks Google.com

The Chinese web monitoring website, GreatFire.org, first reported the issue at 1pm (GMT) today, Friday, 9 November stating in a tweet: "Latest! It appears that Google Search is now blocked in China. Tested in many locations."

This is the first time this has happened since the website began tracking online censorship in February last year.

As well as Google.com being inaccessible, a number of other Google services are also reportedly offline. Gmail, Google Maps, the Google Play store, Google Analytics and more are all currently "DNS poisoned" according to GreatFire.org.

Domain Name System (DNS) is the global system which converts domain names (eg www.ibtimes.co.uk) into an IP addresses (such as 1.2.3.4). DNS Poisoning refers to the intentional manipulation of this system such that a domain name does not resolve to a correct IP address.

The Communist Party of China is currently holding its 18th Party Congress in which new leaders of the party and the country are formally chosen. "The fact that Google is blocked now is surely no coincidence. The big question is whether it will be unblocked again once the congress is over," a blog post by on GreatFire.org states.

Great Firewall

The website has been set up to  as a way of monitoring what is known as the Great Firewall of China - the censorship or blocking of vast swathes of the internet. Mainstream services such as Twitter and Facebook are banned in China.

When someone in China tries to access Google.com or any of the other services mentioned above, they are redirected to an IP address which is located in Korea, and doesn't serve any website at all.

However, at the time of publication, other Google search URLs, such as google.co.uk or google.au, were still accessible from inside China.

Google is the fifth most popular site in China, which has an online population of over 500 million people. "Never before have so many people been affected by a decision to block a website," GreatFire.org said in its blog post.

This is the latest incident in a long line of disputes between Google and the Chinese government. Back in January 2010 Google announced that it would no longer abide by the Chinese government's rules which forced Google to censor search results.

This was in response to a Chinese-originated hacking attack on them and other US firms, including the hacking of thousands of Gmail accounts belonging to human rights activists.

In March of that year Google began to redirect queries from Google.cn to Google.com.hk (Google Hong Kong) thereby bypassing Chinese regulators and allowing uncensored Simplified Chinese results.

A week after this change took place, Google.com went down in China for 10 hours for some still-unknown reason, though sub-domains for mail, maps and documents were unaffected this time.

It is unclear if this block will be temporary or is a more permanent decision by the Chinese authorities.