Major Japanese mobile communications provider KDDI says it has fully restored services following a nationwide network disruption that lasted 86 hours.

KDDI officials announced on Tuesday afternoon that they confirmed its service operations were fully resumed as of 3:36 p.m., and that individual customers and businesses are able to use services as usual.

The problem began at 1:35 a.m. on Saturday and affected voice calls and data communications of KDDI's "au" mobile service, as well as UQ mobile and povo, which use the same network.

A wide range of services provided by "au" including those for weather data and freight train operations could not be accessed.

KDDI officials say more than 39 million users may have been affected.

Japan's communications ministry is considering administrative instructions to the company, as it failed to fully inform users even though the malfunction continued for an extended period of time.