Sergey Brin said Google agreed to the censorship demands only after Chinese authorities blocked its service.
Brin described China’s demands as a "set of rules that we weren't comfortable with" but added that Google’s competitors complied with the same demands without international criticism.
"We felt that perhaps we could compromise our principles but provide ultimately more information for the Chinese and be a more effective service and perhaps make more of a difference," Brin said.
Google's China-approved web service leaves out politically sensitive information that might be retrieved during searches, such as details about the Tiananmen Square suppression in June 1989.
Its agreement with China has provoked criticism from human rights groups.
"Perhaps now the principled approach makes more sense," Brin said.
Brin said Google was trying to improve its censored search service, Google.cn, before deciding whether to reverse course.
He said virtually all the company's customers in China use the uncensored service.
Chinese-based internet users trying to access Google’s main have recently complained about problems website ranging from intermittent access failure to sustained blockage.
Google said it had received notice of the access difficulties and was investigating the cause. "We are currently looking into these reports but as yet don't know why these access problems are occurring," said Cui Jin, a Google official.
Google is just one of the websites recently affected by access problems. Internet users have reported problems accessing email accounts and online chat servers linked to servers overseas including Google's Gmail and MSN Hotmail accounts.
The Paris-based group Reporters Without Borders has said the main website, http://www.google.com/, is no longer accessible in most Chinese provinces due to censorship and criticised the "unprecedented level of internet filtering in China."
The group linked the access problems to the passing of the 17th anniversary of the Tiananmen Square crackdown on June 4.
An official from the ministry of information industry, China's internet regulator, admitted she had also had trouble accessing Google, but declined to comment further.