Irish mobile phone users pay on average five times more for their calls than users in the cheapest EU country do, according to new data from the European Union.
The country with the least expensive mobile phone costs is Lithuania, where consumers pay 1.9 cent per minute.
In Ireland, the cost per minute is 10.2 cent. The most expensive country is the Netherlands at 14.7 cent per minute.
The EU average is 9.1 cent. There is a 774% difference between the cheapest and the most expensive.
According to the European Commission, these price differences cannot be explained by differences in quality, differences in the cost of providing the service, or by differences between countries in consumer purchasing power.
The differentials in other categories of goods and services across Europe are much smaller.
"As these numbers clearly show, the 28 national telecoms markets in Europe today are not benefiting consumers like a single market would. It is critical for the whole EU to move quickly to build a real single market to achieve a truly connected continent," European Commission Vice President, Neelie Kroes said.
Neelie Kroes will present a new package aimed at strengthening the telecoms single market next month.