New Zealand Rugby on Thursday lamented the failure of a plan to create an annual global tournament, which faltered amid objections to the idea teams could be relegated from the Six Nations championship.
The Kiwis had championed the creation of a new cross-hemisphere Nations Championship, with the winners and runners-up in Europe's Six Nations taking on their southern counterparts in an expanded six-nation Rugby Championship.
Supporters said the plan would generate much-needed television revenue, make mid-year tests more consequential and bring Pacific Island nations and Japan into regular competitions.
However, a controversial idea to introduce promotion and relegation to both championships was met with trepidation from unions who would run a huge financial risk if teams were relegated.
"Creating a new international competition was always going to be a challenging conversation for world rugby nations," NZR Chief Executive Steve Tew said.
Praising World Rugby's efforts to get the deal through, Tew said: "We sought to find a model that balanced demands of fans, with the welfare of all players, growing the commercial strength of our competition and ensuring we were providing a pathway for other nations."
He urged national unions not to give up on plans to overhaul the game, and said the southern hemisphere would try to find "opportunities for Pacific unions and emerging nations to grow the game".
"While there were some serious issues to be resolved, such as the varying positions on promotion/relegation, New Zealand Rugby remained committed to continuing dialogue to see if these could be overcome for the greater good of the game," he said.