Japan and Fiji are expected to be confirmed as the two guest nations to join the Six Nations sides in an inaugural eight-team tournament in November and December.
Negotiations between unions and clubs are continuing this week about the completion of the 2020 fixture schedule and proposals to restructure the global calendar.
The World Rugby council meeting which had been scheduled for today to vote on allowing international rugby to be played in October as well as November, has been postponed until mid-July to allow for talks to continue.
Sources indicated last night that it was "the most likely option" that the new-look tournament would replace the scheduled matches against southern-hemisphere opposition, because of Covid-19 travel restrictions, and the delay to the start of the southern hemisphere's Rugby Championship.
Ireland had been due to face Australia, South Africa and Japan at the Aviva Stadium in November, but those fixtures are set to be replaced by a tournament involving two pools of four, with matches played on November 14, 21 and 28.
The final would take place on December 5.
The more contentious issue surrounds the completion of this season's Six Nations matches and how that impacts on Premiership Rugby's aim of completing its campaign. With the Champions Cup final scheduled for October 17, the English clubs have earmarked the following weekend for their final.
However, with England's outstanding Six Nations match against Italy pencilled in for October 31, that could mean that no members of Eddie Jones's squad would be available for the Premiership final.
Talks about the global calendar are even more complex, with the clubs in England and France raising objections to a proposal by the World Rugby working group representing the Six Nations and southern hemisphere nations to move the July window for Test matches to October to create a new international series.
(© Daily Telegraph, London)