Annual revenues at telecom firm Energis Ireland, the third-largest fixed-line operator, were flat last year at €43 million as the company lost internet dial-up custom to groups with broadband services.
The company has also reported that its earnings before interest, tax, depreciation and amortisation (EBITDA) remained unchanged at €1.3 million in the year to the end of last March.
Energis Ireland chief executive Conal Henry said that narrowband internet customers were migrating to broadband at a faster rate than anticipated.
"Obviously people are moving to broadband but the regulatory environment precludes us from entering that market."
Mr Henry said the company's strategy was to replace that broadband business with long-term contracts in the corporate market.
Its customers include supermarket group, Tesco, and Viridian, the former Northern Ireland electricity company, which is making inroads into the market in the Republic.
While the company's British-based parent said it had won new contracts worth €1.3 billion in the year, Mr Henry said that some of that business was not as lucrative in its early phase due to start-up investment.
"We've delivered against the plan that we've laid out and we're comfortable with that. We're proud of our numbers," he said.
The figures for the Irish business were made public as the parent company reported a £25 million sterling (€37 million)drop in its overall sales to £745 million in the year.
The parent company said the impact of falling narrowband internet business masked the impact on its revenues of a 9 per cent increase in sales on other activities.
Overall, EBITDA fell to £116 million from £125 million a year earlier.
The Irish division of the company recently called on ComReg to break up Eircom, arguing that the former State monopoly's dominance of the market was damaging the economy.
In a submission to ComReg's ongoing review of the sector, the company said Eircom's retail unit should be separated from its networks division in order to stimulate investment in the network and foster fair competition in the industry.
The company claimed that Eircom's access to its network gave it lower costs and more control of the standard of service it provided and the service its rivals provided.
