The two cables snapped in three places about 30km off the coast of Shantou, in China's southern Guangdong province. The breaks occurred at the segment connecting Hong Kong and Shantou and segments of the China-US cable connecting Shantou to Taiwan and Japan, said Reach Networks, the cables' operator.
Efforts to repair the cables are currently underway, the company said.
The damage to the cables is believed to have been caused by ships dragging their anchors along the seabed during Typhoon Nari, which is affecting the area, Woo said.
The greatest disruption of Internet services was felt in Australia and Hong Kong. The Hong Kong-based ISP, Netvigator, confirmed that its users had been affected by the cable breaks but declined to comment on the extent of the effect on users.
International phone traffic has not been disrupted by the breaks, as any overflow is automatically handled through alternative routings to the same carriers or via other overseas administrations, Reach said in a statement.