Google Inc's top lawyer has said that the world's leading search engine is asking the US and European governments to press China to lift Internet censorship, describing it as an unfair barrier to free trade.

David Drummond yesterday told reporters that western states should defend the free trade in information with the same kind of rules that they use to complain of China's below-cost sale of products.

He said government talks are "the only way that it's going to change, that this tide of censorship or this rising censorship is going to be arrested."

The company sparred with Chinese leaders earlier this year when it stopped self-censoring its search results in line with Chinese rules after it said Chinese hackers had tried to plunder its software coding and hijack the Gmail accounts of human rights activists.

Since late March, Google has been redirecting search requests from mainland China to Hong Kong, which doesn't have the same restrictions.

"The cyber attack was sort of the final straw because we felt that it was increasingly hard to do business there in accordance with our values," Drummond said, describing the company as in danger of becoming "part of the same apparatus" of Chinese state censorship.