SingTel is facing an investigation by the IDA after two service disruptions in as many days.
The unrelated disruptions occurred Tuesday and Wednesday this week and have since been fully resolved.
According to a SingTel statement released Wednesday evening, the Tuesday evening disruption lasted more than four hours and resulted in customers in northern and western parts of the country being unable to use 3G voice, data and SMS services.
The Wednesday morning disruption lasted more than three hours and led to certain users being unable to use 3G Internet services.
The first incident was traced to a hardware issue while the second was traced to a software glitch affecting the firm’s mobile Internet data network serving the western part of the island.
An IDA spokesperson told The Straits Times that the regulator was investigating the incidents and would take appropriate action when necessary.
SingTel’s issues mark the latest in a string of service disruptions that have hit all three of the country’s carriers in less than a year.
A software glitch last September resulted in service disruptions for SingTel customers in various parts of the island over two days.
Singapore’s second largest carrier StarHub was hit by a power failure the next month that led to some users being unable to make voice calls for a few hours.
The country’s smallest carrier by subscriber number M1 was affected last May by a massive outage that made subscribers in certain parts of the island unable to connect to its network.
M1 was fined S$300,000 ($233,000) for the incident in November.