Six Aviva Premiership teams, six clubs from France’s Top 14 competition and seven of the RaboDirect Pro12 sides are expected to qualify for the 20-team competition.
The final place would be taken by the winner of a play-off involving clubs from several competitions, including the second-tier tournament that is to replace the Amlin Challenge Cup.
There is also expected to be a new third-tier competition in September, from which two qualifiers would then take part in the second-tier tournament opening it up to clubs from outside the Six Nations countries such as Georgia, Russia, Spain, Romania, Portugal and Belgium.
It is understood an agreement is very close, and once signed all parties can then chase a resolution between broadcasters BT Sport and Sky, both of whom have indicated a willingness to agree a compromise TV rights deal.
Sky Sports managing director Barney Francis said earlier this month: “We are absolutely willing to take part in conversations that lead to a solution that is in the best interests of the game and for the fans. But it will take compromise and compromise between all parties.”
European Rugby Cup, the governing body of the Heineken Cup, will be wound up in the summer.
A replacement body will be set up, with its name and the name of the new tournament yet to be finalised. The Six Nations committee is expected to provide the basis of the new governing body, with some ERC staff retained.
The new qualifying criteria would have implications for Scottish clubs, with Glasgow and Edinburgh losing their automatic passage into the elite European tournament.
As things stand, Glasgow would qualify for next season’s new competition but Edinburgh would not, based on their respective positions in the RaboDirect Pro12. Glasgow are fifth and Edinburgh eighth but both teams have seven league matches still to play, including a game against each other.