Former All Blacks coach John Hart has blasted the proposed new test format and also expressed major fears for the state of New Zealand rugby.
Hart told Stuff that the annual global test concept would dilute the World Cup and fail because it would be too uneven.
Top rugby officials including New Zealand Rugby chief executive Steve Tew met in Los Angeles last week to review the idea, whose major proponents is World Rugby vice chairman Agustin Pichot.
Hart also called on New Zealand rugby to be split into professional and participation streams.
"My fear for New Zealand rugby is not the All Blacks," said Hart, the NZR appointee on the new Blues board.
"It's the bottom end of the game where I see clubs struggling and schoolboys stopping playing the game.
"That's largely because as a country we have not invested in the amateur game."
Hart reiterated comments he first made decades ago warning the amateur game faced ruin if money did not trickle down from the top.
"I'm really worried about where we are with the game when you see the numbers dropping off in secondary schools," he said.
"It's not because of professionalism, it's the game itself that is struggling.
"The physicality is turning people away. It's a really difficult game to play and what people see at the top is what they see through the age-groups.
"We need a step change to say let's build participation, and have a participation stream and a high performance stream, and make sure we broaden our horizons."
Hart has always been seen as one of rugby's best thinkers and communicators, a corporate heavyweight, and a man whose successes included being a key component in the Auckland Warriors drive to the NRL league grand final in 2011.
Hart called on schools rugby to rewrite rules for the game at that level.
"We've got to take the physicality down, bring in skill and let kids enjoy it," he said.
"If our schools are really keen on participation they should be looking at sevens."
His opposition to the Pichot concept was based on a belief that a regular, quasi world championship would become boring. He wanted a global season with normal tours including Lions ventures continuing.
"The Nations Championship will put money in people's pockets, but it will be the same pockets it's going into now," he said.
"It's a short-term solution to a funding issue and getting more equitable money into the southern hemisphere, but it doesn't solves the problems we face."