The Six Nations and SANZAAR have issued a joint statement outlining their plan to launch a new tournament in 2026 in the existing July and November international rugby windows.
All of the Six Nations and SANZAAR teams will compete and will be joined by two invitational unions.
The 12-team tournament would involve all of the teams from the Six Nations and the four from the southern hemisphere's Rugby Championship - including the All Blacks.
Six Nations and SANZAAR will own and operate the elite competition, with World Rugby creating a newly formed second-tier competition to facilitate promotion and relegation matches.
A statement read: "Six Nations Rugby and SANZAAR are working in partnership, alongside global rugby stakeholders, to bring to life a new international rugby competition that will be played in the existing July and November test windows.
"The creation of the new competition has been a collective process from the sport, including World Rugby, unions, key leagues, competitions, and crucially, the International Rugby Players.
"Set to begin in 2026, the new elite competition will feature all the Six Nations Rugby and SANZAAR teams, with two spaces reserved for invitational unions to join the southern hemisphere group. A transparent selection process will be managed by SANZAAR, supported by World Rugby and the International Rugby Players, to determine these two invitational unions.
The statement said the new tournament would be owned and operated by Six Nations Rugby and SANZAAR, taking place in alternating years, outside of the British and Irish Lions Tours and Rugby World Cup.
"Involved at every stage of developing the new competition, has been the International Rugby Players. This connection has been key in supporting the wider conversations around the club and international calendar taking place in parallel, and ensuring player welfare has remained a fundamental priority in all decision-making.
"To strengthen the development pathway for emerging nations, World Rugby will create a second-tier competition that will feature teams from Europe and the rest of the world, with Six Nations Rugby and SANZAAR actively involved in cementing the link between the two divisions.
"Establishing the two competitions will pave the way for promotion and relegation matches, contributing towards a valuable pathway for teams, and will support ambitions to sustain and grow the global game."
