Google Inc's e-mail service, Gmail, was reported out of service in China over the weekend, and it was intermittent and still unstable on Tuesday.

Over the weekend, many netizens said they could not receive or send mail via the service or even log in to Gmail using third-party applications.

Cui Yin, 26, a Beijing resident who is studying in the United States, returned to China last weekend and has been experiencing Gmail problems.

"I planned to help my mother register a visa to the US, but now I cannot check the mail," Cui said. "The disconnection may delay my mother's visit to the US next year."

She also said she could not receive e-mails from her university in the US, adding that some other classmates of hers have also been affected.

A representative of Google told Global Times on Monday that technicians checked its data servers after receiving reports from Chinese netizens but did not find anything wrong.

The Cyberspace Administration of China, the nation's Internet watchdog, responded on Tuesday that it had "no reply" about the problem.

Foreign Ministry spokeswoman Hua Chunying said on Monday that she didn't understand the problem, but China always welcomes and approves of foreign investors doing businesses in the country under the law.