Web surfers hoping to visit sites ending in .se found themselves unable to get through.
The Swedish web blackout was caused by problems associated with maintenance work performed by the Internet Infrastructure Foundation (Stiftelsen för internetinfrastruktur – .SE).
The Foundation is responsible for administering .se top domain and registering websites which end in .se.
The error occurred on Monday night when routine service work was scheduled to take place.
“It must have occurred due to a bug in our system which led to us sending out faulty information. We saw it right away,” said .SE head Danny Aerts to the TT news agency late on Monday night.
He said the error took place around 10pm and immediately caused major problems for people attempting to access sites ending in .se.
For an unknown reason, an extra .se was added to the end of web addresses.
“We don't know how it happened, but we're going to investigate,” said Aerts.
The glitch has also resulted in continuing email problems for many Swedes as emails sent during the outage have been unable to find the addresses to which they were sent.
While large Swedish internet providers such as TeliaSonera and Bredbandsbolaget have updated their systems to correct the problem, many smaller operators – which account for roughly 20 percent of Sweden's internet traffic – have yet to fix update their systems, the Göteborgs-Posten (GP) newspaper reports.
.SE spokesperson Maria Eklund told the GP that the issues may not be completely resolved before Wednesday.
"This little mistake is going to affect internet traffic for two days," she told the newspaper.