Full capacity to Telstra Australia's international Internet network should be restored early this week, according to the telco.
Stuart Gray, Telstra's public affairs manager for online services, said: "To repair the break, remote controlled submersibles will dive to the cable and bring it to the surface. The two ends of the cable will be spliced in with new cable, then spliced together and the cable relaid."
Gray said the SEA-ME-WE3 cable will take "a matter of days" to repair and that basically it was just a high-tech "welding job".
The 39,000-kilometre cable links Australia, Asia and Europe and its damage resulted in access disruptions last week for millions of Internet users across the three continents. The cable was damaged 63km from shore south of Singapore, sitting in 25 metres of water at about 3.20pm AEDT on Tuesday November 21.
The cause of the damage in the Jakarta-Singapore link of the cable was unknown at deadline, but "there have been no signs of an earthquake. So it could have been a fishing trawler or rock movement; we don't know," Gray said.
Telstra is Australia's biggest Internet service provider (ISP) with more than 650,000 customers. Hundreds of other Australian ISPs also use it.
SingTel is coordinating repair operations on behalf of the consortium of 90 companies from around the world which own the cable, including Telstra, France Telecom and Hong Kong Telecom.
Gray said traffic was redirected from the western route cable, which normally takes 50 per cent of Telstra's international traffic, to the eastern route cable. The network would remain at 75 per cent capacity until the cable was repaired.
"There has been sufficient unused capacity in the eastern-route cable to cope with the traffic. Currently, we are looking for extra capacity so we have a buffer in case anything else goes wrong."
Gray said he had heard that Japan, Hong Kong, Singapore, Indonesia and even the UK and US had felt the impact of the damaged cable, but that the level of impact had been variable. "As we have been able to redirect capacity, so have other countries."
The SEA-ME-WE3 began operations last year and is the world's longest telecommunications system. Until November 15, it was Australia's biggest connection to the Internet, now held by Southern Cross Cable network, running from the East Coast of Australia to the US.