After heavy snowfalls closed the Gotthard and San Bernardino tunnels to heavy goods vehicles for several hours on Friday, drivers have been advised to avoid Switzerland.
In the morning, trucks from Italy were being stopped at the Chiasso-Brogeda border point and those travelling south were redirected to waiting bays on the A2 motorway, the Federal Roads Authority said.
Although the tunnels were reopened around midday, trucks are only being let through in small numbers and there are warnings of long delays.
The Gotthard road tunnel is on the main north-south artery through Switzerland and is the most busy route for the 1.2 million trucks that cross the Swiss Alps annually.
Up to 20cm of snow fell in central and northern Ticino on Thursday night. Forecasters said a depression over the southern Alps could bring up to 60cm of fresh snow on Friday.
swissinfo.ch and agencies