In a note published on the eBay-owned company's website, Skype said the system had not crashed or been victim of a cyber attack, but problems occurred because of a "deficiency" in the programs that link client software downloaded onto customer computers with Skype's own network software.

Skype is probably the best known voice over internet protocol (VoIP) provider and telecoms analysts have been predicting since the late 1990s that this much cheaper method of placing calls would eventually put traditional telcos out of business.

Although Skype's problems last week attracted acres of press coverage, analysts did not see it as halting the growing migration to VoIP communications.

US telecoms commentator Jeff Kagan highlighted the fact that VoIP is a complex data service, unlike a relatively simple email, and is still a developing technology.

"It is still very young and will occasionally have hiccups, " he said.

Pat Kidney, managing analyst with Dublin-based telecoms consultancy AnalysysMason, said the scale of Skype's problem was worrying, but the outlook for VoIP was still bright.

"This might give the image of the technology a blow, but the fundamentals of VoIP are solid and ultimately its resilience and redundancy are now likely to be improved, " he said.

Kidney said the impact on Irish business was likely to be minimal because the vast majority of Irish firms which use VoIP do not use Skype's free service, but commercial operators with service agreements. However businesses which do rely on VoIP should always still have a traditional PSTN line as a back up.

"It's much the same way a company that relies on its broadband connection should have an ISDN line as a back up for business continuity, " he warned.