Call for parity in EU mobile costs
Mobile phone users in Ireland are paying up to five times more than customers in other countries in Europe.
Latest figures show people living in Lithuania - also in the EU - pay on average less than two cent a minute to make domestic calls on their mobile phones.
That compares to more than 10 cent per minute in Ireland. The overall average in the European Union is around 9 cent.
Neelie Kroes, vice president of the European Commission, has warned mobile operators that new measures will be brought in to help create more equal charges across the continent.
"As these numbers clearly show, the 28 national telecoms markets in Europe today are not benefiting consumers like a single market would," she said.
"It is critical for the whole EU to move quickly to build a real single market to achieve a truly connected continent."
The Netherlands is the most expensive country in the EU for making mobile phone calls, with an average bill of more than 14 cent a minute.
Ireland ranks ninth most expensive out of the 28 member states.
The EU said the price differences cannot be explained by differences in quality of mobile networks, costs of providing the services or consumer purchasing power.
There is much less price differences between countries in the price of basic goods, such as milk, or even occasional purchases like an iPad, the EU pointed out.
Ms Kroes said she will bring in new measures to strengthen the telecoms single market in September.