The introduction of a new software platform for online trading at Comet has disrupted web sales and affected the electrical company's quarterly results.
Sluggish online growth failed to offset total sales at Comet between November to January, which fell by 7.3% compared to the same period the previous year.
Web-generated sales grew by just 3%, reflecting some disruption during the introduction of the new software platform in November, the company said.
However, Matt Piner, senior retail analyst at retail research firm Verdict, said online growth was weak before the introduction of the new platform.
Dixons has also showed a similar falling rate of online sales growth, suggesting that online electricals retailing might be beginning to reach maturity, he said.
"A clear picture is emerging that the electricals market was one of the biggest losers over Christmas and the beginning of 2011 looks set to be equally challenging.
"Unfortunately for Comet it looks set to be one of the main losers in the poorly-performing sector," he added.
Comet is part of European electrical company Kesa, which saw total sales grow by just 0.4% for the period. Comet uses RightNow's software as a service-based system to support customers.