The crack in the Gotthard Road Tunnel that appeared on Sunday - leading to its closure - has been confirmed as caused by "redistribution of tension" within the rock above the structure.
Bern ruled out any reason linked to the ageing of the tunnel.
Part of the false ceiling had already suffered similar damage in 1985 - just five years after the tunnel opened.
Swiss Transport Minister Albert Rösti expects the tunnel to be open again by the end of the week at the latest.
Waits of more than 2 hours at the Gotthard Tunnel over the weekend
The predictions were correct - traffic through the Gotthard Tunnel was extremely heavy over the weekend.
Plane hit by lightning while approaching Geneva
Passengers on a BA flight heading into Geneva had a shock on Sunday evening when the plane had to abort a landing after it was struck by lightning.
Erasmus return by next year in doubt
Switzerland’s planned return to the EU’s Erasmus student exchange programme by next year is now facing uncertainty.
Lack of French on food packets worry shoppers
Shoppers in french speaking switzerland are increasingly seeing food packaging without any French language details - and it’s perfectly legal.
More keeping their own chickens
Chickens are fast becoming everyday pets in Switzerland, with around seventy thousand households now keeping them, according to federal authorities.
Pro-Vélo Geneva restarts 'Cycling Saturdays'
Cyclists in Geneva can look forward to a new season of “Bike Saturdays” starting this weekend.
