UK ecommerce businesses which register a dot com domain name are at risk of losing nearly half of their local business.

The study, from UK company Usability by Design, claimed that people associate a dot com domain name with the US and will avoid shopping through the site.

A web survey of 140 people by the consultancy found that 43 per cent of respondents assume a dot com web address means the site is based in the US. According to the company, users associate dot com domains with hidden or confusing shopping charges and increased delivery times.

Graham Bunker, director of Usability by Design, said: "During our testing we asked users why they didn't select dot com sites. Most users had shopped at dot com sites before and encountered problems. These ranged from minor problems such as converting from dollars to pounds, and having more complex purchasing models to sites not delivering outside the US."

"Many companies based in the UK are taking on a dot com address because they feel it gives them a global appearance, but they could potentially be losing out."

Lesley Cowley, operational director at Nominet, the national registry for domain names ending with dot uk, said: "The findings are not a surprise to us. People are increasingly familiar with the dot uk web address and recognise that it is a company based here. The dot uk can assure consumers that UK standards and laws will apply."

The number of sites registering a dot uk domain name has grown dramatically over the past six months, Cowley said. More than one million websites have a .uk address and Nominet registers over 150,000 sites per month.