Google has previously reported that its traffic has been interfered with in China, but has never gone so far as directly accusing the authorities.
However, as complaints over technical glitches and performance issues mount from both end users and advertisers, Google has upped its rhetoric.
"There is no technical issue on our side. We have checked extensively," Google said in a statement quoted by several newspapers. "This is a government blockage carefully designed to look like the problem is with Gmail."
The accusation comes in the wake of a government crackdown aimed at disrupting the so-called “Jasmine Revolution” - a group of online dissidents following in the footsteps of protesters in the Middle East - which Google claims has included online attacks against activists and the online services they use.
“We’ve noticed some highly targeted and apparently politically motivated attacks against our users,” Google said in blog post at the time.
“We believe activists may have been a specific target. We’ve also seen attacks against users of another popular social site. All these attacks abuse a publicly-disclosed MHTML vulnerability - with the Internet Explorer browser affected.”
Google considers these attacks particularly serious because they exploit an entire web service, rather than targeting end-user computers.
“The abuse of this vulnerability is interesting because it represents a new quality in the exploitation of web-level vulnerabilities,” the company said. “To date, similar attacks have focused on directly compromising users' systems, as opposed to leveraging vulnerabilities to interact with web services.”