Telco SingTel will hold a press conference at 1pm on Thursday to provide further details on the extent of the fire that broke out at a building housing key Internet equipment on Wednesday, and restoration efforts.

The fire that started at 2pm at SingTel's Bukit Panjang building brought down banking, telecommunications and even betting services in many parts of Singapore for hours.

SingTel said the fire disabled its fixed-line voice, Internet, pay-TV and mobile services in the northern part of Singapore, including Choa Chu Kang, Upper Bukit Timah and Woodlands. Internet links of SingTel's corporate customers including several major banks and telco StarHub were also disrupted.

StarHub on Thursday morning said it had managed to restore most of its cable services digital voice services. In a Facebook post, it said 90 per cent of its services affected by the fire have been restored as of 8am on Thursday.

The Straits Times understands that it is still trying to restore its fibre broadband services. The telco said its services were affected by the damage caused by the fire because it leases some SingTel optical fibre capacity that runs through this facility.

Meanwhile, telco M1 said that "a number" of fibre broadband services have been restored on Thursday morning to affected customers. It did not provide further details.

The Infocomm Development Authority (IDA) said its officials visited the site on Wednesday night to assess the situation and extent of damage caused by the fire.

"The operators and their contractors have been working overnight to recover and reconnect the damaged fibre cables. We note that services are being restored progressively and urge the operators to update the public regularly, while their engineers work to fully restore services," it wrote in a Facebook post.