The Internet Corporation for Assigned Names and Numbers (ICANN) said it would begin negotiations soon to iron out technical issues and prices for the new web addresses.
Adult-oriented sites, representing a US$12billion (A$16b) industry, are expected to begin buying “xxx” addresses within the next six months.
The US$60 price tag is roughly ten times higher than prices for dot-com names.
The new pornography suffix was among 10 under consideration by the regulatory group, which also recently approved addresses ending in “jobs” and “travel.”
Regulators hope the voluntary adoption by adult websites of the “xxx” domain will protect children from accidentally viewing pornography.
By labeling themselves clearly, filtering software will more effectively block access to those sites.
But critics dispute the claim, pointing out that as the scheme is not compulsory, sex sites will still be able to retain their old dot-com domain names.
Over the years efforts to ban or segregate online pornography have failed.
In 1996 the US Congress prohibited the “knowing transmission” of obscene or indecent messages to anyone under 18 years old.
But a year later the Supreme Court struck the law down on the grounds that it was too broad.
A narrower 1998 attempt was never enforced due to a court challenge.
In the past ICANN, an international non-profit body, has resisted attempts to set up a domain for sex sites on the grounds it doesn’t want to regulate online content.
“As a technical coordinator, we don’t pass judgment over content on the Internet,” said spokesman Kieran Baker, adding it had no problems with the .xxx domain as it will be run by the private sector.