The National Transport Authority, which regulates the taxi industry, has said any vehicles and their drivers that carry passengers for payment must meet the relevant licensing requirements.

The warning follows protests by thousands of taxi drivers around Europe today.

The drivers were demonstrating over a perceived failure by the authorities in their respective countries to properly regulate taxi and private car hire smartphone apps. 

In particular, the taxi drivers are concerned about Uber, the limousine booking app, which enables users to call a private car to take them from one place to another.

Taxi drivers claim the app is being exploited by drivers who are not licensed, and who have not reached the required standards of regulated taxis. 

As a result, the taxi unions claim the app is putting passengers at risk and taking away business from the licensed members of the industry. 

There was significant disruption to taxi services in a number of European cities today, including London, Madrid and Paris.

Taxi drivers in Ireland did not take part in the protest. 

However, the National Irish Taxi Association claims there is growing concern among drivers about the increasing number of unlicensed drivers using apps such as Uber and Wundercar.

Jerry Brennan, General Secretary of NITA, said the issue was creating dangers for taxi users and is very hard to police. 

He called on the National Transport Authority to implement preventative measures to stop these apps from enabling unlicensed drivers to pick up fares.

However, Uber claims its drivers all meet local regulations and have been subjected to insurance and general background checks.

It said today's reaction is coming from an industry that has not faced competition for decades, and companies like it are now offering that choice. 

Uber was founded in San Francisco in 2009 and last week secured another $1.2bn in funding, bringing its value to an estimated $18.2bn. 

German based Wundercar, which has been operating here since the start of the month, told RTÉ News that safety is one of its main priorities, and all its drivers go through a particular checking process, including online checks and offline procedures, including sending a copy of their passport and conducting a Skype interview.

The company claimed this goes far beyond the requirements of a garda vetting certificate. 

It said it is not a taxi services, and therefore should not be regulated like one, but does operate within the law as it exists for people who regularly share resources. 

The NTA said it has sought and obtained assurances from Uber that its drivers here are all licensed in accordance with taxi, hackney or limousine regulations.

The NTA said it is currently in the process of contacting Wundercar, to seek similar assurances.

It said all drivers are subject to the same enforcement regime and penalties.