Irish flyhalf Jonny Sexton and All Black great Richie McCaw have urged rugby leaders to move the June internationals and adopt an integrated global season to improve player welfare and safeguard the future of the game.
The pair threw their weight behind a proposal by the International Rugby Players' Association (IRPA) to make the changes for the 2016 season that would help all test playing nations to pick their best players.
The IRPA want to move the June test window back to the end of July, allowing the Southern Hemisphere-based players to finish the Super Rugby club season, while those in Europe would start their domestic campaigns later, possibly October.
McCaw said it was an opportunity to make a significant and beneficial change.
"If the game's leaders give this idea, or a variation of it, serious consideration it could be a game-changer for professional rugby," the 116 times capped flanker said in a statement.
"It would be fantastic to address this long standing season structure debate once and for all, the players and the game would be so much better for it."
Sexton, who started all three tests in the British and Irish Lions' recent test series win over Australia, agreed.
"We see this initiative as beneficial for the global game," the flyhalf said.
"From a player perspective, we urge our leaders to get in a room together, take a positive attitude and see what can be done."
The IRPA said existing windows for World Cups, Six Nations, the Rugby Championship and November tests would not change and that 'preliminary discussions have already started with some National Unions.'
Calendar complaints have been a long-standing issue in rugby, coupled with the growing demands on players through increased physicality and number of matches.
Currently, European countries tour Southern Hemisphere sides in June with return matches held in November and December. The timing means teams always tour at the end of their ever growing seasons.
With hosting teams retaining all profits from the matches, ticket sales suffer if fans sense a mismatch or know a travelling side are lacking their star names.
In 1998, England were heavily criticised by Australia for sending a hugely understrength side to play the Wallabies in a June test which the home side predictably won 76-0.
The Lions were also unhappy with Australia for holding back their international players for warm up matches against their Super Rugby franchises in June, leaving them short of competitive action before the tests.
The IRPA said the moves for greater communication would improve the likelihood of all teams, including smaller nations like the Pacific Islanders, fielding their strongest sides and would also see the Lions play full strength provincial sides ahead of the 2017 series against New Zealand.
"We're in a unique position - for the first time since rugby went professional, the major Northern and Southern Hemisphere competition and commercial structures are on the table at the same time," IRPA chairman Damian Hopley said in a statement.
"This is the ideal time to seriously consider change that will secure player welfare initiatives."