Chinese foreign ministry spokesman Qin Gang told reporters that Google's move was an isolated act by a commercial company and should not affect China-US ties "unless politicised" by others.
The government would handle the Google case "according to the law", he added.
Earlier an official in the Chinese government office which oversees the internet said: "Google has violated its written promise it made when entering the Chinese market by stopping filtering its searching service and blaming China in insinuation for alleged hacker attacks.
"This is totally wrong. We're uncompromisingly opposed to the politicisation of commercial issues, and express our discontent and indignation to Google for its unreasonable accusations and conducts," the unnamed official was quoted as saying by Chinese state news agency Xinhua.
Chen Yafei, a Chinese information technology specialist, told Reuters that Google should have accepted Chinese regulation if it wanted to operate in the country.
"Any company entering China should abide by Chinese laws," he said. "Chinese internet users will have no regrets if Google withdraws."
Google's Peter Barron on decision
Edward Yu, chief executive of Analysys International, a Beijing-based research firm specialising in technology issues, said he did not believe Google's rerouting was sustainable.
"The thing that makes the government unhappy is this kind of gesture," he said. "They may set up barriers against Google."
Young Chinese professionals working in Beijing's main IT hub, Zhongguancun, expressed a mixture of regret, anger and surprise on Tuesday at Google's decision.
"I think it was inevitable though," Chen Wen, 28, told Reuters. "The government was never going to compromise on filtering. China needs this company. It's a great loss for the country."
You Chuanbo, 25, predicted the government would "just end up blocking access to all of Google".
In Beijing, some passers-by laid flowers outside Google's offices to thank the company for standing up for its principles.
1) Users accessing the Chinese site Google.cn are redirected to the Hong Kong site Google.com.hk
2) The searches are carried out on the servers in Hong Kong and are sent back to the users in mainland China
3) On the way, the results are filtered by the Chinese government
International human rights groups praised Google's move , with the New York-based Human Rights in China saying Google had put the ball in Beijing's court - China promised to respect freedoms in Hong Kong when it regained the territory in 1997.
Robert Mahoney, deputy director of the Committee to Protect Journalists, said the CPJ hoped it would "ramp up pressure on the Chinese government to allow its citizens to access the news and information they need".
A Paris-based rights group, Reporters Without Borders, called Google's decision a bold move which other internet companies should follow. Foreign internet companies have to comply with China's stringent censorship rules before being allowed to operate in the country.
Announcing the decision, Google's chief legal officer, David Drummond, said that providing uncensored searches through the Hong Kong-based google.com.hk website was "entirely legal" and would "meaningfully increase access to information for people in China".
The company said it would maintain a research and development and sales presence in China, where about 700 of its 20,000 employees are based.
Google spokeswoman Marsha Wang told AFP news agency she had no information about job losses or a possible transfer of staff to Hong Kong offices, saying only that "adjustments" could be made "according to business demand".
Google is not the biggest search provider in China and its mainland Chinese operation accounts for just a fraction of the firm's total sales.
However, the US giant risks losing market share, revenue and staff to rivals which include market leader Baidu, up-and-comer Tencent and US heavyweight Microsoft, Reuters notes in a commentary.
Tom Online Inc, an internet company owned by Hong Kong's richest man, the billionaire Li Ka-shing, has stopped using Google's search engine in protest, it said, against Google's lack of compliance with Chinese regulations.
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