DAVOS - Top NGOs including Greenpeace and Amnesty International called for the $1.1 billion sale of the .org internet domain to a private company to be blocked on Wednesday, saying it could do "irreparable harm".
Registrations for the millions of nonprofits whose websites end in .org are overseen by the Internet Society (ISOC), but in November the U.S. nonprofit announced it was selling control to a year-old private equity firm called Ethos Capital.
Since then, hundreds of organisations have objected, worried that Ethos will raise registration and renewal prices, cut back on infrastructure and security spending, or make deals to sell sensitive data or allow censorship or surveillance.
On Wednesday, the directors of 10 leading NGOs published an open letter at the World Economic Forum (WEF) meeting in Davos urging ISOC and ICANN, the internet's governing authority, to stop the sale, to stop the sale.
"Should the governance and stewardship of .ORG end up under the control of private or other actors that could lead to financial or other barriers that would irreparably harm global civil society," the letter read.
Brett Solomon, executive director of digital rights group Access Now, said the sale risked pricing smaller organisations off the internet. But he said that was "really just a symptom of a broader issue around control".
"The entity that is responsible for the stewardship of the Public Interest Registry has access to everything," he told the Thomson Reuters Foundation by phone.
"They have a capacity to take somebody off the .org domain, which means they can censor, they can monitor, they can deny.
"And all these issues are very, very important for organizations who are challenging governments and are challenging powerful interests."
ICANN, which has the power to veto the deal, did not respond to a request for comment.
The Internet Society said in a joint statement with Ethos that the company had committed to limiting any cost increase to an annual average of 10%.
It said agreements in place with ICANN contained limitations to prevent a domain registry from selling information about registered organisations.
Domain operators were not supposed to censor content, but could in some cases intervene to take down material such as child sexual abuse images, the statement said.
Concerns about the sale have also been raised by the United Nations special rapporteurs for freedom of expression, assembly and association and a group of U.S. lawmakers including presidential candidate Elizabeth Warren.
"Certain public goods should never be for sale," Kenneth Roth, executive director of Human Rights Watch said in a statement.
"We don't auction off the town square. Similarly, ICANN shouldn't approve the sale of .ORG, which is the essential haven where civic groups gather the world over."