A glitch in the Government's computer network left many public officers without access to their e-mail messages for about a day on Monday.
It did not, however, affect public e-services offered through government websites.
A spokesman for the Infocomm Development Authority (IDA) said that the glitch led users to experience "intermittent network access", which was detected at about 9am.
"Efforts to restore services commenced immediately. Despite the breakdown, officers continued with their daily work," the spokesman added.
The affected organisations included the Ministry of Education, Ministry of Communications and Information, National Library Board, Singapore Land Authority and National Heritage Board (NHB).
By lunch time, some public officers said e-mail services were up and running. The network was fully restored by about 8.30pm.
Mr Clement Teo, senior analyst at technology research company Forrester, said that it was premature to pinpoint the causes of the glitch. IT systems, he said, can malfunction as a result of software problems, hardware failures and human errors.
The IDA said it is looking into the cause and "will take the necessary follow-up actions".
Public officers interviewed said they used USB drives to pass files around, or turned to their personal e-mail accounts.
"It's not that dire," said an officer at a statutory board.
"There are some things we don't need e-mail to sort out, like doing reports, because the information we need is already stored in the computer, and we passed files around through our thumbdrives."
An NHB officer said she took the chance to work in a more personal way. "I normally communicate with my colleagues through e-mail, but today, I picked up the phone to call for clarifications and walked over for face-to-face discussions," she said.