The Asia Pacific Gateway (APG) cable has been under maintenance since June 6 and it is not clear when this work would be completed, said a Internet Service Provider (ISP) representative who did not want to be named.

The maintenance work could affect internet connections through the APG, but the impact would not be significant and would be within calculations, the representative said.

Meanwhile, the Asia Africa Europe (AAE-1) cable encountered a problem on May 26. The management unit for the cable said the problem might have been caused by an optic fiber breakage on one of the cable's segments.

Many internet users in Vietnam have of late reported slow speed at certain times, and the customer service websites of several ISPs have seen feedback saying their users have problems when accessing international websites like Facebook or Google.

The representatives of certain ISPs said Internet connection has been re-routed to other cables to maintain normal Internet speed.

The APG cable runs 10,400 kilometers (6,460 miles) under the Pacific Ocean, linking Japan with Hong Kong, mainland China, Malaysia, Singapore, South Korea, Taiwan, Thailand, and Vietnam.

The AAE-1 is a 25,000-km submarine communications cable system running from Southeast Asia to Europe through Egypt.