Domian name owners have been urged to be wary of demands for re-registration fees.

According to .uk domain name registry Nominet, more than ten thousand people in the UK received what appeared to be invoices from a company, UK Internet Registry Ltd, demanding money to register the .com version of their .uk website name.

Nominet claimed that because they were printed on pink paper (the same as Nominet invoices) and used similar colours to the Nominet logo, that people may have believed they were from it.

"Many people believed that these letters were invoices asking them to re-register their.co.uk domains as well," explained a Nominet representative.

Domain name owners should check that they are the admin contact for the domain name, and should check the name of their registrar, Nominet said.

Nominet is taking legal action in Australia against the company, alleging that it had infringed Nominet's copyright.

UK Internet Registry Ltd will also face charges that the invoices were misleading and contrary to the Australian Federal Fair Trade Practices Act and the Western Australian State Fair Trade Act.

The respondents in the action are Bradley Norrish and Chesley Rafferty, and companies UK Internet Registry Ltd (a Seychelles company), Internet Payments Pty Ltd and Diverse Internet Pty Ltd (both Australian companies).

Mr Rafferty and another affiliated company, Domain Names Australia (DNA) were found guilty by Judge Finkelstein in the Federal Court of Australia earlier this month of false representation.

DNA had sent out mailshots to over half a million businesses in Australia soliciting business for domains, or variants of, they already held or had held previously. Rafferty and DNA were barred from sending further related letters for three years.

Neither Mr Rafferty nor Mr Norrish had replied to requests for comment at the time of publication.