The damage was probably caused by a ship's anchor or a sand dredge pulling the cable along but the actual cause won't be known for a few days, according to Telstra spokesman Stuart Gray.
"The repair ship is at the location (of the damage) but they haven't pulled the cable up yet," he said in a telephone interview. Even when the cable is pulled up, it may not be immediately apparent what caused the damage, Gray said.
To repair the break, remote-controlled submarines will go down to the cable, at a location approximately 70 kilometres south of Singapore, and bring it up to the surface. The two ends of the cable will be spliced in with new cable and then spliced together. This procedure typically takes a few days.
Australian Internet users have been hardest hit by the cable break as up to 60 per cent of the country's international Internet data traffic was carried by the SEA-ME-WE 3 cable (SEA-ME-WE stands for Southeast Asia-Middle East-Western Europe).
An Australian government report said that Internet capacity had been reduced by 50 per cent because of the accident.
Many countries in the region rely on just one or two cables for the bulk of their overseas Internet traffic and are therefore vulnerable to similar accidents. The September 1999 earthquake in Taiwan, which damaged the Asia-Pacific Cable Network (APCN), effectively isolated Singapore from the global Internet for several hours.
Telstra, in Sydney, can be reached via the Web at http://www.telstra.com/. More information about the SEA-ME-WE 3 cable can be found at http://www.smw3.com/.