Train staff are unable to carry out the checks, which have been ordered by the Italian government, the Swiss Federal Railways (SBB) said on Tuesday, according to Reuters.
The move to suspend the trains is in place indefinitely and affects dozens of daily cross-border services, including 'EuroCity' connections and long-distance trains between Milan and Frankfurt.
Regional trains that connect the two countries, which are used by thousands of cross-border workers are also affected.
Switzerland and neighbouring Italy, Germany and France had already reduced train services in November, but the Italian government introduced new requirements due to the surge in cases during the second wave of the pandemic.
That has resulted in the train services being halted as they were during the first wave back in spring.
Italy did not explicitly forbid train travel abroad, but its requirements — including for passengers’ temperatures to be measured — exceed the capacity of train personnel, an SBB spokeswoman told Reuters, leading to the decision to suspend the Swiss-Italian routes.
“Swiss Federal Railways trains will travel only to the country’s border to Italy,” SBB said.
Italy, France and Germany have also introduced new requirements meant to prevent skiers from travelling over the holidays to Switzerland and Austria, where resorts are due to be open for limited, locals-only skiing.
The SBB has promised to refund people who purchased tickets, reports 20 Minutes.