Fears are increasing that Danish telecommunications companies are getting ready to block the free use of services like Skype and Apple's free SMS service. 

Telenor, TDC and Telia have all written language into their standard conditions that says that they may block Skype and similar services from any mobile phone, laptop or tablet computer that can be used to call or send text messages.

At Telia, 80 percent of their network is used by data traffic while 80 percent of its revenue comes from voice services.

"We need to have price plans that hang together," Telia spokesperson Mette Honoré told Berlingske newspaper.

She said that the company could not continue to pour billions of kroner into expanding mobile networks if they couldn’t find ways to generate income.

Many cellular operators worldwide – including some companies in the US, the UK, France and Spain – prohibit their customers from downloading Skype’s software or outlaw the use of voice over the internet phone services in their standard sales contracts. Other carriers have imposed fees to undermine Skype’s attraction. Barriers to Skype and similar Internet calling services are coming under increasing scrutiny as the internet goes mobile. By 2013, the number of internet-ready mobile phones will surpass the number of computers in the world for the first time, according to Gartner, a research firm.

Most operators and network equipment makers see Skype and other Internet phone call providers as freeloaders, stealing their customers while they invest billions of dollars to build out and upgrade mobile networks.

Honoré said that Telia would not go out on the limb and be the first Danish company to start charging, but that “there is no question that something is coming."

Telenor’s legal director Nicholai Kramer Pfeiffer told Berlingske that his company only put the language in its agreements in order to be prepared to deal with the issue “if the opportunity arises, but not at this time".

Honoré said that should any changes happen, they would be done above board and in a clear and honest fashion. She said that the intent of any possible change was not to single out Skype.

“We want to bundle the packages together, so customers can chose the one that works best for them,” she said.

Economist Martin Salamon of Forbrugerrådet, the consumer council, was highly critical of the idea of charging for the previously free services.

"The telephone companies are setting the stage for a violation of net neutrality by restricting access to the free internet,” Salamon told Berlingske.

Trine Bramsen (Socialdemokraterne), a government IT spokesman, said she was “shocked” and will introduce legislation guaranteeing that customers can continue to use Skype and other services for free.

“When they write it into their contracts, it must mean that they intend to charge,” she told Berlingske. “We need to look at whether we can lay down rules to ensure users' net neutrality through stricter legislation.”

Bramsen said she would ask the business and growth minister, Ole Sohn (Socialistisk Folkeparti), who is in charge of the Danish telecommunications market, to plan a conference call with all of the telecom companies to discuss the issue.

"We might as well have a completely clear law, so both consumers and telecom companies know what we think," said Bramsen.