Switzerland said that mandatory quarantine would be imposed on travellers arriving from 15 more countries, including Britain, Belgium and the Netherlands, due to their coronavirus infection rates.
The 10-day quarantine restrictions, aimed at stemming the spread of the novel coronavirus, come into force from Monday.
The requirement will also apply to seven other European countries - Denmark, Hungary, Iceland, Ireland, Luxembourg, Portugal and Slovenia - plus Ecuador, Jamaica, Morocco, Nepal and Oman.
Quarantine is already imposed on arrivals from 44 other countries, including Argentina, Brazil, India, Spain and the United States.
Areas of Switzerland's neighbours France, Italy and Austria are also on the list, with Brittany, Liguria and Lower and Upper Austria being added from Monday.
"People who have spent time in a country or area with an increased risk of infection and then enter Switzerland must go into quarantine," the health ministry said.
Switzerland defines such countries as ones where the infection rate over the last 14 days is more than 60 per 100,000 people.
The wealthy Alpine country said Friday that its own rate was 61.7 over the previous fortnight.