New Zealand Rugby boss Steve Tew is threatening to break away from rugby’s future tour program if the urgent need for a global season isn’t addressed.

Tew is running out of patience with the existing international calendar which he says is unsustainable and doesn’t reward the All Blacks for their crowd-pulling capacity.

NZ Rugby has refused to schedule any Tests beyond 2019, effectively telling world bosses they need to produce a superior structure

He told allblacks.com he is was pleased to have the chance to raise the subject with World Rugby bosses recently but is probably not any closer to resolving an issue which he says is strangling the international game.

“We don’t believe the current system is sustainable,” he said.

“Our players and the northern hemisphere players won’t sustain that and I think it’s fair to say the French and English clubs don’t think it is sustainable either.”

NZ Rugby will consider negotiating their Tests for 2020 if there was no progress made on the issue, Tew added.

While World Rugby chairman Bernard Lapasset had done a good job during his tenure in growing the game and getting it into the Olympics, Tew believes it’s time to make the global season a priority.

Lapasset is stepping down in July and looks set to be replaced by former England captain Bill Beaumont, whose nomination was seconded by Tew.

Under the current structure, there are three-week inter-hemisphere windows in June and November, while the Six Nations and Rugby Championship are also held at opposite ends of the calendar year – all squeezed into increasingly busy domestic calendars.

The June Tests cut into the latter weeks of Super Rugby and often lack credibility because of the under-strength and tired nature of the northern hemisphere tourists.

The November internationals draw big crowds in Europe but Tew believes they are inherently unfair as they don’t compensate the world champion All Blacks financially for their pulling power, with all ticket revenue soaked up by the host nation.