The UN copyright agency saw a 15 percent increase in "cybersquatting" complaints last year.
The World Intellectual Property Organization, which handles arbitration for more than half of the world's cybersquatting disputes each year, registered 1,823 complaints in 2006 alleging abusive registrations of trademarks as Internet domain names.
The complaints came mainly from IT companies, banks and the world's top pharmaceutical firms, as well as famous fashion brands and the entertainment industry.
The growing number of professional domain name dealers who use computer software that automatically registers expired domain names or temporarily registers them without paying charges, is of concern to trademark owners, WIPO said.
"Domain names used to be primarily specific identifiers of business and other Internet users, but many names nowadays are mere commodities for speculative gain," said WIPO's deputy director-general, Francis Gurry.