The Danish supreme court on Thursday ratified fines given to four Uber drivers for operating illegally, paving the way for similar fines on a further 1,500 drivers.
The four taxi drivers, one of whom was fined DKK 486,500 ($78,060), were charged with failing to have permits and for violating a law introduced to combat Uber which imposed extra rules on taxis operating in Denmark.
After launching its service in Denmark in 2014, Uber Technologies was criticised by taxi driver unions, companies and politicians who said the company posed unfair competition by not meeting legal standards required for established taxi firms.
"We are very disappointed for the drivers involved and our top priority is to support them during this difficult time," an Uber spokeswoman said.
"We are changing the way we do business and are operating in line with local laws across Europe, connecting with professionally licensed drivers," she said.
The landmark case means the police can issue a fine for each individual ride made by Uber's more than 1,500 drivers in the country between 2014 and 2017.
A spokesman for the Copenhagen police said it would assess the verdict and decide next week how to proceed.
Parliament passed a law in February 2017 that introduced more stringent requirements on taxis, such as mandatory fare meters and seat sensors. The new rules prompted Uber's withdrawal.
The company has previously said it would pay any fine given to its drivers, according to Danish newspaper Berlingske.