The foreign ministry has advised Swiss visitors to Thailand that although a coup has taken place in the country, there is no immediate risk.
By its estimates there are around 10,000 Swiss currently in Thailand. The southeast Asian country is a popular choice with sun-seeking Swiss tourists.
The Thai military staged the putsch late on Tuesday night as the country's prime minister was attending the 61st United Nations General Assembly session in New York. Martial law has been imposed and political gatherings have been banned.
"It is calm at present, but it is uncertain how the situation will develop," the Swiss foreign ministry said in a statement on its website. "Check the media for developments and stay in touch with your travel operator."
The statement also advised Swiss nationals to follow the instructions given by local authorities and to avoid demonstrations of any kind.
Some 4,700 Swiss are registered as permanent residents in Thailand. Around 1,300 Swiss tourists were also estimated to be in the country on Tuesday.
Business as usual
Swiss travel firms said there were no reports of any problems in the main tourist areas, including Phuket. Even in the capital, Bangkok, it was "business as usual" for foreign visitors, according to a spokesman for Tui Switzerland.
Tui and other leading operators conceded that scenes of armoured vehicles in the streets of Bangkok had alarmed some would-be visitors, and they had handled many phone calls from people seeking information about the situation.
Thailand is a popular travel destination for the Swiss, with 150,000 visiting the country every year. September is still low season, with the main flood of tourists from Switzerland not getting underway until November.
The southeast Asian nation is an important trading partner for Switzerland, and Swiss exports to the country have trebled in the past decade to SFr934 million ($746 million). Over the same period Swiss imports from Thailand have almost doubled to SFr723 million.
Swiss firms with operations in Thailand include the world number two cement maker, Holcim. A spokesman for Holcim said local staff had reported that the situation was calm and business was unaffected.
swissinfo with agencies
4,000 Swiss live in Thailand.
150 Swiss firms do business in Thailand.
150,000 Swiss tourists visit Thailand every year.
Swiss exports to Thailand have trebled in the past decade to SFr934 million ($746 million).
Swiss imports from Thailand have almost doubled over the same period to SFr723 million.
Thailand is Switzerland's second-largest trading partner in the region, after Singapore.
Switzerland is also well-known in Thailand since King Bhumipol spent seven years of his childhood in Switzerland.