China's major web portal Sina.com said Thursday it was re-evaluating cooperation with U.S. Internet search giant Google, but not because of political pressure.

An officer in charge of public relations at Sina made the remarks in response to recent foreign media reports that Google's partners in the Chinese mainland were facing political pressure to abandon the search engine after it rerouted Chinese-language search services to Hong Kong.

The officer told Xinhua on condition of anonymity that they were rethinking the relationship because Google was apparently not meeting Sina's standards for foreign partners.

"All partners of Sina must abide by Chinese laws and regulations as well as have long-term plans to operate in China," the officer said.

Google's withdrawal to Hong Kong came on March 23, more than two months after it voiced dissatisfactions over censoring search results in the Chinese mainland and intentions to leave the market.

Shortly after the withdrawal, several of Google's partners have announced plans to cut off or re-assess their ties with the company.

Tom Group, owned by Hong Kong's richest man Li Ka-shing, said last week it had deleted links to Google's search engine on its web portal, saying that was out of "abiding by China's laws and regulations."

Tianya, the operator of a popular Internet forum in China, said it would negotiate with Google details of their business contacts after the change of search sites.

China Unicom, the second largest Chinese mobile phone operator, did not make it clear to Xinhua if they would terminate cooperation with Google, but its General Manager Lu Yimin recently said all their partners have to comply with Chinese laws and regulations.

Google has kept its research and development unit and some sales teams in the Chinese mainland. Also, all five mainland companies Google has invested in are still in operation.

Yu Guofu, a member of the Policy and Resource Committee of the China Electronic Commerce Association, said Google's partners are mainly web portals out-sourcing part of their operations to search engines and businesses looking for promotion through publishing their key words.

Yu said it is unlikely for web portals to continue cooperating with Google as they normally need partners that are reliable and easy to contact.

Cooperation with the other type of partners would also be affected as fewer web portals would be putting in links to Google, Yu said.

Hu Yanping, director of the Data Center of the China Internet, also believed Google's major cooperation with mainland businesses would fall apart.

"It will be difficult for mainland companies to advertise themselves through the Hong Kong-based Google," Hu said.

Some advertisers in the mainland have said they are considering to turn to alternate platforms for advertisements, including well-known advertising agency the Ogilvy and Mather.