"Telkom is enhancing its ADSL (Asymmetric Digital Subscriber Line) network to support ADSL speeds of up to 10Mbps (megabits per second)," the communications service provider said in a statement on Friday.
The speed upgrade would apply "in all areas which have suitable technology at exchanges to support" it, and would come at no additional cost to customers.
"The 10Mbps ADSL speed is an innovative enhancement to the existing fastest ADSL product, which now allows users to potentially burst at 10Mbps.
"All upgrades therefore remain subject to localised line conditions and the type of equipment available at the nearest exchange.
"The upgrade is focused on 4Mbps users who currently sync at full profile speed," Telkom said.