The foreign ministry has lodged an official complaint with the Libyan authorities after Swiss tourists were denied entry to the North African country.
The Libyan government made an unannounced change on Sunday to entry rules, refusing access to any visitor without a passport from an Arab country or Arabic translation of their passport.
About 40 of the 115 passengers on board a Swiss International Air Lines flight from Zurich to Tripoli on Sunday were refused entry even though they were in possession of a valid visa for Libya.
They were forced to return to Switzerland on the same aircraft later in the day. Around 20 French nationals who arrived on another airline were left stranded at Tripoli airport until Monday. The French ambassador had to intervene on their behalf.
And the nearly 200 passengers on a French charter aircraft which landed in Sebha in the south of Libya were not allowed to disembark, forcing the plane to return to France.
A Swiss foreign ministry spokesman said the Libyan chargé d'affaires was invited to a meeting in Bern on Monday with government officials who expressed their "astonishment" at the move.
The spokesman, Lars Knuchel, told the Swiss news agency that Switzerland had still not been informed officially of the new restrictions.
However, the Swiss government has updated its travel advisory for Libya to include the change.
The next flight by the carrier, Swiss, to Tripoli is scheduled for Tuesday.
An airline spokesman said 60 passengers had reserved seats for the flight but they had been informed that anyone "without an Arab passport or a translation of their passport would not be allowed on the plane".
Analysts say the development reflects confusion in Libyan government policies, since it has made efforts recently to promote itself as a tourist destination.
Tripoli is expected to get a new airport and the national airline, Afriqiyah Airways, is buying new Airbus planes.
And last month, the son of Libyan leader, Moammar Gaddafi, announced plans to promote ecotourism, saying it was time for the oil-dominated country to diversify its economy.
The country has been slowly opening its doors to foreign investment including tourism since 2003 when the United Nations lifted sanctions. This followed Gaddafi's announcement to dismantle the country's nuclear weapons programme.
But less than one per cent of Libya's Gross Domestic Product came from tourism in 2004 – the last year of record – with only 149,000 visitors. The figure pales in comparison with tourist arrivals in other North African states.
About nine million people visited Egypt last year, for example.
swissinfo with agencies
Libya is Switzerland's second-largest trading partner in Africa and provides more than 40% of Swiss crude oil imports.
In 2004 imports from Libya, consisting almost exclusively of petroleum, increased by 4.5% to SFr790 million.
Exports, mainly in the machinery and pharmaceutical industries, soared by 55% to SFr189.5 million in the same year.
Libya has a population of just under six million.