A prolonged 2012 Super series, with four mid-year Tests wedged in the middle, and a heavier travel burden in the new four-team Rugby Championship, will test players like never before.

It could mean top stars playing 36 matches - three more than what Wallabies ironman Will Genia gallantly soldiered through in a World Cup-boosted 2011.

‘‘This is the most difficult season for a Wallaby that I’ve seen,’’ said McKenzie.

‘‘You look at the calendar and it’s tough, really tough.’’

The new June international window will halt the Super Rugby season for four weeks as the Wallabies play a mid-week Test against Scotland and a three-match series against Wales.

Test players will then return to their Super franchises for the final three rounds of the competition before a three-week play-off series starts on July 20.

The rebadged Tri-Nations featuring Argentina, now called the Rugby Championship, kicks off with the Wallabies playing the All Blacks on August 18, a fortnight after the Super final.

There is a third Bledisloe Test and the regular spring tour in Europe to follow.

Former Test prop McKenzie stressed it would be impossible for top stars to play at top capacity throughout a 10-month season.

‘‘It’s not going to happen. You have to manage the players in that space.

‘‘They will tell you they are willing but in the end they can only front so many times,’’ McKenzie said.

Resting and rotation will be the norm at the Reds and the NSW Waratahs, where more than two-thirds of the Test players are based.

McKenzie’s Queensland side and the Waratahs are better than even-money bets to make the play-offs in the Super Rugby series, while the Western Force, Brumbies and Melbourne Rebels are rank outsiders.

McKenzie, who sees squad depth as crucial, believes the mental toll will be bigger than physical factors. ‘‘The Wallabies are playing hard game after hard game so the capacity to integrate those guys back and freshen them up mentally [will be difficult].’’

Super Rugby starts on the weekend of February 24-25.