Chief Legal Officer David Drummond said in a blog posting that Google had already started taking a small percentage of users to a landing page on Google.cn that links to Google.com.hk, and would soon stop all redirecting.
Google shut its Chinese portal in March over censorship concerns and began sending users to its Hong Kong site instead. But the operating license that allows it to use its old web address to send users on is up for renewal on Wednesday.
"It's clear from conversations we have had with Chinese government officials that they find the redirect unacceptable, and that if we continue redirecting users our Internet Content Provider license will not be renewed," Drummond wrote in the blog, posted late on Monday night in the United States.
"Without an ICP license, we can't operate a commercial website like Google.cn so Google would effectively go dark in China," he added.
The new Google page is extremely simple, with an image of the Google logo and a non-functioning search box. Below are short messages saying "We have already moved to google.com.hk" and "Please save our new website." Clicking on much of the page redirects users to the Hong Kong site.
Google said in January it might quit China over censorship and after it was hit by a sophisticated hacking attack that it said came from within China.
It has kept its promise to end self-censorship that was demanded by Beijing as a condition for operating inside China -- prompting the redirecting to Hong Kong -- but is working to maintain a presence inside China.
China's foreign ministry on Tuesday declined comment on Google's decision to end automatic rerouting, but Drummond said he hoped it would be acceptable to the Chinese government.
"This new approach is consistent with our commitment not to self censor and, we believe, with local law. We are therefore hopeful that our license will be renewed on this basis so we can continue to offer our Chinese users services via Google.cn."