In a letter to European ministers meeting in Estonia, the companies said they were deeply concerned about discussions in Brussels over spectrum reform and a failure to create the right framework would affect all industries relying on the internet.

"Failure to establish a well-functioning and investment-friendly spectrum framework risks stifling innovation, growth and development for decades to come," chief executives from nine European telecoms firms wrote.

The letter was signed by the CEOs of Deutsche Telekom (>> Deutsche Telekom), KPN (>> Royal KPN), Orange (>> Orange), Telecom Italia (>> Telecom Italia), Telefonica (>> Telefonica), Telekom Austria (>> Telekom Austria AG), Telenor (>> Telenor), Telia Company (>> TeliaSonera AB) and Vodafone (>> Vodafone Group).

The European Commission has tried for years to coordinate how governments allocate wireless spectrum, or parcels of airwaves, to mobile operators in a bid to create a single European telecoms market.

But about 15 EU countries have balked at the Commission's plans to establish a minimum licence duration of 25 years and a peer review mechanism to review national regulators' draft measures on spectrum allocation.

Licence durations vary across the European Union making it harder for telecoms firms to operate on a larger scale and compete with U.S. rivals.

Member states have in general been very sensitive about any oversight of wireless spectrum by Brussels as the sale of spectrum licences can raise billions of euros for governments.

Telecoms companies strongly support minimum licence durations of 25 years together with a strong presumption of renewal to increase certainty, said Mats Granryd, director general of the GSMA, the global mobile operators association.

"There needs to be a proper working mechanism between me as an operator ... and the government and both of us will work on the presumption that I will continue to own the spectrum for another 25 years against some sort of fee," he told Reuters.

The letter called for a strong peer review mechanism to enable best practices to be shared among countries, as well as to make it easier for operators to share spectrum.

Granryd said voluntary sharing of mobile airwaves allowed operators to cover more areas, such as the countryside, without taking on the full cost, but getting permission from national authorities was very difficult.

"If we have harmonised spectrum, the rest will follow," Granryd said.

(Reporting by Julia Fioretti; editing by David Clarke)

By Julia Fioretti