Warren Gatland fears rugby's British and Irish Lions would lose their mystique if global administrators cut the length of future tours in half.
Coach Gatland warned rugby's governing bodies not to shorten future Lions tours, amid the battle to ease the global fixture pile-up.
World Rugby and top unions are still fighting to plot a future course, with no international calendar in place post the 2019 World Cup.
Next summer's Lions tour opens just one week after the Guinness PRO12 and Aviva Premiership finals - Gatland has long since accepted the 2017 schedule, but insists future trips need extra preparation time.
"I don't have an input but it will be interesting to see how the next deal is structured," said Gatland, worried about the idea of cutting future Lions tours from 10 to five matches.
"You would lose the mystique of what the Lions is all about. Even for the people who are planning to go on the tour but are only going for the last three weeks. You can get excited watching the first games on TV and seeing the crowds.
"The Lions is unique in terms of a team touring the southern hemisphere because they never get to experience what we get to experience in the Six Nations and potentially going forward - on some of the Lions' occasions 40 per cent of the crowd being away fans."
Gatland led the Lions to a series victory over Australia in 2013, then promptly called for extra preparation time in his post-tour report.
Lions coaches have been calling for more tour preparation time since at least the early nineties, and Gatland believes rugby's power-brokers must be able to make that happen.
"I understand the pressures that the Lions and the board are under and there is a lot of external stuff from the clubs, the unions and the different competitions about release of players and how long they are going to be off," he said.
"That is all part of the next negotiations. Clubs do get compensated for the players coming away.
"Hopefully when the next deal is done the stake holders will sit around the table and thrash out what will be the best thing.
"Having been involved in this, I would hate to see the Lions die as an entity and not have the opportunity to prepare properly."