China's telecommunications companies have dispatched five vessels to repair subsea cables damaged in the earthquake that rocked Taiwan on Tuesday.

Five boats have departed to the scene with two of them having started to repair the damaged lines, said a senior executive with China Netcom.

The broken cables, which have hindered Internet operations across China, would be refloated and repaired by crews on the vessels, but aftershocks had made the work difficult, said industry insiders.

Guan Ruoqi, general-manager of the international department of China Netcom, China's second largest telecom operator, said on Friday the repair of fiber-optic cables would start soon.

China Netcom's overseas call services were basically restored with the private leased circuit to Hong Kong totally repaired.

China Netcom's Internet business had risen back to one-fifth of the normal levels.

China Telecom, China's largest telecom operator, said its call services and a private leased circuit had been basically restored with the international Internet circuit recovering by 15 percent and the international exit width reaching 60 percent of normal levels.

However, Internet access to North America was still suffering a serious log jam, said China Telecom.

Zeng Jianqiu, professor with the Beijing University of Posts and Telecommunications, said telecom enterprises should establish emergency response projects to reduce users' losses to a minimum.

At an on-line survey conducted by Sina.com, 90 percent of the respondents admitted their lives or work have been affected by inaccessibility to the Internet and more than 50 percent said they or their companies had incurred losses.

The government and telecom operators should issue detailed information about the causes, recovery process and alternative solutions as soon as possible to prevent chaos, said the expert.

Zeng emphasized telecom operators should increase investment in technology research and development of undersea cable maintenance and repair.

The emergency impelled enterprises to search for balance between effective back-up and cost control.

A quake measuring 7.2 on the Richter scale off the southern tip of Taiwan damaged all nine fiber-optic cables that cross the ocean floor south of Taiwan, affecting telecommunication traffic between the mainland and Taiwan, Hong Kong, the United States, Southeast Asia and Europe.