Companies that failed to win their chosen .biz domain have 30 days to prove a legal claim over the name, but only if they pre-registered an interest last year with Neulevel, the company that manages the top-level domain.

Following claims in the US that the allocation of .biz domains was an "illegal lottery", the 39,000 .biz domains that received multiple applications have now been allocated using a round robin system.

Jennie-Marie Idler, senior manager for Europe at Neulevel, said: "The dispute resolution process begins now.

"If there is an IP claim against a name that's been allocated then the registrant has the option to proceed with the dispute resolution process. They need to prove they have a legitimate business claim to the domain name."

Around 650,000 .biz domains have now gone live since it was opened up in November, but half of the initial 2.4 million applications were for just 39,000 names.

Neulevel had to cancel applications for duplicate domain names made under the original process in response to a Californian lawsuit accusing .biz of running an illegal lottery.

Separately, .us domain names will go live on 24 April. Non-US businesses are entitled to register a .us domain if they have significant activity or dealings in the country.

"It is ideal for non-US companies that want to establish a US presence," said Idler.

Users respond more readily to a domain for the country in which they are located and companies will be more easily able to establish a US presence, she explained.