By Jonathan Fildes
Technology reporter, BBC News
The two groups have different business models for the domain
Rival environmental groups are lining up supporters to try to take control of a new net domain aimed at green groups.
At least two consortiums are known to be preparing bids to control .eco.
In March this year, former US vice president Al Gore backed a bid by the California group Dot Eco to operate the proposed "top level domain" (TLD).
But now a Canadian environmental group known as Big Room has launched a competing bid to manage the TLD, which is similar to .com or .uk.
Both firms plan to apply to Icann - the regulatory body that oversees domain names - for the creation of .eco early in 2010.
"We're two different applicants with two different business ideas," Minor Childers, co-founder of Dot Eco, told BBC News.
"Ours is to sell domain names to raise funds for organisations who can effect change."
He said the group had already entered into contracts with its supporters - such as the Sierra Club and the Alliance for Climate Protection - to give away 57% of its profits from sales.
"We could be one of the biggest contributors to environmental causes anywhere in the world," said Mr Childers.
Big Room also plans to generate money from the sale of .eco domain names to fund "sustainability projects around the world".
However, the consortium, which includes WWF International and Green Cross, also believe that .eco could be used as a labelling system to endorse companies with green credentials.
Al Gore won a Nobel Prize in 2007 for his environmental work
".eco should mean something and it should be about something more than just another domain," Trevor Bowden told BBC News.
Companies and organisations that apply for .eco domains through Big Room would have to meet certain criteria to be granted a web address.
For example, the company may have to measure and publish its carbon footprint to apply.
"This could evolve over time - this is not about us deciding what is green and what is not," said Mr Bowden.
The criteria would be drawn up with the help of international organisations, he said.
Mr Bowden envisages that the companies would use the .eco sites to publish all of their green information.
"We think transparency is a really powerful tool," he said.
Mr Childers said that his scheme would also require applicants to prove their green credentials but would probably not be as strict.
"It's unrealistic to think that you will get a lot of sign-ups if you're too restrictive," he said.
"I think our websites should give the opportunity for the 13-year-old environmentalist to have a website as well as a business," he said.
Despite having differences about a model for .eco, Mr Childers said that both groups would "definitely have to sit down" together at some point.
"My only problem is that I think labelling is a really poor use of this opportunity," he said.
The .eco domain has been made possible because of a relaxation on Icann's strict rules on top-level domain names.
The decision, made last year, means that companies could turn brands into web addresses, while individuals could use their names.
As a result, either group could apply for a different domain.
However, for the moment, both sides have one goal.
".eco is our sole focus," said Mr Bowden.