Many Eircell customers could face higher prices for mobile phone top-up cards in some newsagents from next week because of a bitter dispute between retailers and the mobile phone company.

Some retailers want to add a surcharge of 4 per cent for each top-up card sold because Eircell has decided to introduce a lower retail margin for its "Go cards".

This type of top-up card is purchased by hundreds of thousands of mobile phone users who sign up to Eircell's pre-paid mobile phone service, Ready to Go.

At present, customers can buy top up cards worth £20 (€25.39), £10 or £5 from retailers who receive a payment worth 10 per cent of the purchase price of the sale. But from November 7th Eircell will reduce this retail margin to 6 per cent to boost the popularity of an alternative electronic top-up method.

But the National Federation of Retail Newsagents, which represents 750 outlets nationwide, said yesterday some members would surcharge the cards to maintain margins.

This would mean customers would pay £20.80 for a card offering £20 call credit, £10.80 for £10 of call credit and £5.20 for £5 of credit.

Mr Joe Holmes, chief executive of the National Federation of Retail Newsagents, described Eircell's decision as a cynical attempt to force agents from selling physical mobile phone cards to move to electronic top-up.

He said the federation had made an official complaint to the Competition Authority citing an abuse of Vodafone Eircell's dominant position. An Eircell spokeswoman confirmed the firm would reduce retail margins next week but denied it was dominant in the Irish market.

She said the company could not prevent retailers from adding surcharges to its top-up cards. However, consumers would still be able to purchase call credit from more than 8,000 retail outlets using electronic top-up machines.

Meteor and Digifone said yesterday they had no immediate plans to reduce retail margins below 10 per cent.