Plans for the porn-only domain have been widely criticised

The domain for sex sites was approved in June and final negotiations over how it should be run were due to conclude in early December.

This latest delay is because the net body that oversees the creation of new domains said it needed more time to review a report on .xxx before granting final approval.

No date was given for when the review of the report would be completed.

Slow start

The idea for an .xxx domain was first floated in 2001 and since then has gradually inched towards approval.

The domain was widely expected to achieve final approval at the Internet Corporation for Assigned Names and Numbers (Icann) meeting held in Vancouver from 30 November to 4 December.

However, Icann chairman Vint Cerf unexpectedly announced at the meeting that the decision was being delayed as the organisation and governments wanted more time to argue about the merits of setting up such a domain.

Icann is waiting for a report from its own Governmental Advisory Committee on .xxx that a review committee had yet to read and decide upon. No timetable was given for when the work of this committee would be finished.

In August, the final decision was postponed following a request from the US Department of Commerce which had "concerns" about the domain.

Plans for the .xxx have been criticised by many people and organisations, among them former Icann board member Karl Auerbach and US conservative religious groups, including the Family Research Council.

ICM Registry, the company that proposed and plans to run the .xxx, said the domain would make it easier to find and filter pornographic material online.