SINGAPORE (THE BUSINESS TIMES) - The Singapore Exchange (SGX), which experienced an outage in its Web services at around the market close on Tuesday evening, had said it expected to restore its services that same day.

The Business Times managed to access the website again at around 8.40pm, some four hours after the difficulties began.

Asked by BT on Tuesday about whether a cyber attack or malicious cause had been ruled out, a spokesperson for SGX said: "There is no indication that our systems were compromised."

She also reiterated that there was no impact on trading, in a statement later uploaded to the bourse's Twitter account.

The trouble began at around 4.30pm, an issue which SGX attributed to a domain name system (DNS) issue. The DNS is like the phone book of the Internet, and ensures that numeric addresses direct to the correct alphabetical website names.

Mainboard-listed telco StarHub and office trust OUE Commercial Reit were among the companies due to release financial results on Tuesday. But the calendar is now on an unplanned break, as visitors to the website face an error message from Singapore-based Internet service provider Vodien.

SGX wrote on Twitter at 6.08pm that while the recovery effort was under way, "site availability across all network providers will vary in the meantime and full restoration will be gradual".

Users were asked to visit brokers' websites or "alternative sources" for price information and issuer announcements.

The bourse operator said it was working with its DNS partner to understand the root cause of the downtime, said its spokesperson.

"Our trading and clearing systems are separate from the website and there was no impact on trading in our markets," she said. "We apologise for the inconvenience caused."

Additional reporting by Charmaine Ng