SINGAPORE - Some Singtel customers found themselves unable to connect to the Internet from home using fibre broadband on Tuesday (June 8) following overnight maintenance.

The telco said about 3 per cent of its fibre broadband customers were affected.

Service was progressively restored through the day and was fully up in the evening, said Singtel, more than 12 hours after dozens of customers began reporting connection problems, starting at about 5am.

However, some customers said they were still not able to connect on Tuesday night.

The Infocomm Media Development Authority (IMDA), Singapore's telecommunications regulator, said that it is investigating the disruption and will take enforcement action if there are any lapses.

It told Singtel to "restore services expeditiously" and update affected users on the recovery processes.

"IMDA takes a serious view of any service disruption to public telecommunications services, especially when many are home," it added.

Singtel acknowledged the downtime in a Facebook post at 7.50am. By 9am, almost 1,000 reports of outages had been logged on outage tracking website Downdetector.

This led to customers of Singapore's largest telco voicing their frustrations as they faced difficulties working from home, which is the default mode of working in Singapore amid tightened Covid-19 measures.

Many resorted to using their mobile data to connect online instead of using home broadband and Wi-Fi.

In a Facebook update at about 6.15pm on Tuesday, Singtel told customers: "We recognise that it has been a trying time as many of you are working from home, and we are very sorry for the disruption."

The telco said its engineers are still investigating the cause of the issue, which affected customers in the central and eastern parts of Singapore.

This included Tampines, Pasir Ris, Sengkang, Punggol, Bedok, Kallang, Mountbatten and Tiong Bahru, according to comments on Singtel's Facebook posts.

"We are taking this incident very seriously and are taking steps to review our processes to prevent a recurrence," Singtel added.

To compensate affected customers, the telco said they will be offered a 10 per cent discount on their monthly broadband subscription, which will be reflected in their July bill.

Those who also have a Singtel mobile subscription plan and received an SMS from the telco will have their local mobile data charges waived for Tuesday.

According to updated information on Downdetector, the number of reported outages for the telco peaked at around 1,500 just before 12.15pm.

Singtel's first Facebook post on the outage racked up more than 600 comments by Tuesday night. A second post on the matter at about 9.50am drew about 1,700 comments.

Some people had reported outages as early as between 1am and 2am, but it was unclear if this was due to the maintenance.

"I hope your crisis management or product team can comprehend that many of us are working from home," wrote Facebook user Wilson See Wei Ren. "The least you could do is to relax the data usage or bandwidth (quota) of our mobile phones since that's the only way for us to stay connected."

Many people also asked why Singtel did not notify them earlier of the maintenance and why it had to be done during a time when working from home was the norm.

And while it is now the June school holidays, the downtime affected some who were still doing home-based learning.

Mr Felix Wu, 43, said that the outage made it difficult for his 10-year-old son to do his online holiday homework and he would have to catch up later.

The executive, who works in the healthcare sector, realised his home Internet was not working at 7am, and his connection was restored only at about 5pm.

"The downtime was a bit too long," said Mr Wu, who usually works from home but had to return to his office on Tuesday.

Earlier, Singtel advised customers who had issues connecting online to reboot all their routers and power them back on after one to three minutes, to help "resynchronise and refresh the connection".

However, many customers who tried this said it did not work for them and they were still unable to connect online.

Singtel later said in an update at around 9.50am that it was aware that some customers were still experiencing issues with their connection.

In December last year, M1 users were hit by a fibre broadband outage that drew 6,400 comments on an M1 Facebook post on the matter.

Downdetector logged around 9,800 outage reports for M1 at one point.

A second M1 fibre disruption later in the same month logged a peak of more than 12,000 outage reports.