Innsbruck airport refused to allow 110 British tourists’ entry into Austria over the new Covid rules.
Police said many were probably caught out by a new rule requiring a negative PCR test within 48 hours.
Austrian opposition politicians blamed the health minister for failing to update restrictions on the internet.
Most of the tourists returned home immediately, but 40 spent the night in a hotel.
Of those 40, 12 underwent new PCR tests and continue with their holidays, the local authority in Innsbruck said.
Austria has imposed last week a nationwide lockdown for people who did not receive their full vaccination against COVID-19.
The move aimed at slowing the fast spread of the disease in the country. The move went into effect at midnight on Sunday.
The new measure prohibits unvaccinated individuals older than age 12 from leaving their homes except for basic activities such as working, grocery shopping, going for a walk or getting vaccinated.
The lockdown will affects about 2 million people in the country of 8.9 million people.
“It’s our job as the government of Austria to protect the people,” Chancellor Alexander Schallenberg said.
“Therefore we decided that starting Monday … there will be a lockdown for the unvaccinated.”
Europe is facing 500,000 more Covid deaths by February, World Health Organisation (WHO) warns.
The agency also sounded alarm over a surge in cases and bemoaned stuttering vaccination rollouts on parts of the continent.
And in a dire new warning, WHO regional director Hans Kluge said the pace of transmission across the region was of “grave concern.”
“We are, once again, at the epicenter,” Kluge said in a statement.
The WHO has earlier warned that a new coronavirus “variant of interest” named Mu, also known by its scientific name as B.1.621.