Telecom operator Elisa reported problems with its landline network on Wednesday. The interruption began around 3.35 pm.
"We don't have an exact idea yet of the reason for or extent of the disruption so far. We know that we've had widespread interruptions in data transfer," Elisa Service Management Director Lasse Huttunen, told Yle.
Huttunen said that many customers reported problems with internet usage on Wednesday afternoon and evening.
"Some websites can be reached but not others," Huttunen added.
He said there was reason to believe that the problem is nationwide.
"But it is showing up in that some traffic is being blocked and not others. There does not right now seem to be a total national blackout. But we know there are problems."
Huttunen later added that the problems seem to be related to fibre optic cables linking Finland to Sweden. He said the glitch did not appear to be directly affecting telephone service, but that it may do so later. Mobile web services are affected.
"Primarily this is a case of problems for internet users. Since we have not yet been able to isolate the source of the problem, we cannot estimate the timetable for fixing it," he said after 5 pm.
There were also disruptions in Saunalahti's internet services, which use the same cable network.
At 3.55 pm the service provider published an advisory on the disruption on its Finnish-language website. At that time it indicated that the problems began at around 10.54 am.
After 6pm, the newspaper Helsingin Sanomat quoted an Elisa representative as saying the problem was due to a digger breaking an underground cable in the southern town of Lohja.
Huttunen confirmed this to Yle, saying that a repair crew was at the scene. He said it remained unclear how long it would take to fix the rupture, but that it would likely be several hours.
Since connections to the rest of the world via Sweden seem to be cut off, traffic is being re-routed through Tallinn, Estonia, which is causing overloading, he added.
Elisa said in a statement Thursday that service had been restored by 5.33 am Thursday.
Update: This story was edited to reflect the fact that Elisa issued its first advisory (in Finnish) on the service disruption on its website at 3.55 pm. It has also been updated to reflect Elisa's statement that service was restored fully at 5.33 am Thursday morning.
26.11.
26.11.
26.11.
26.11.
26.11.