France striker Kylian Mbappe and Poland forward Robert Lewandowski have voiced concerns over holding a World Cup every two years.
Fifa has proposed a biennial World Cup rather than holding it every four years as part of a revamped calendar.
The governing body told delegates at a summit that a biennial World Cup would generate more than £3.3bn in additional revenue over a four-year cycle.
“The World Cup is the World Cup,” said Paris St-Germain forward Mbappe.
“It’s a special thing because it’s something [held] every four years.”
Uefa, Europe’s major leagues and South American football’s governing body Conmebol have opposed the plans.
Caf, the African governing body, has given its backing.
“[It is] the best thing, the best competition in the world,” added 23-year-old Mbappe, who helped France win the 2018 World Cup.
“If you hold it every two years, it can start to be normal to play [in the] World Cup. I want to say that’s not normal. That [should be] something amazing.
“We play over 60 games in a year. You have Euros, the World Cup, now the Nations League – so many competitions. We are happy to play but when it’s too much, it’s too much. We have to recover, we have to stay relaxed.
“If people want to see quality in the game, the emotion, to see what makes the beauty of football, I think we have to respect the health of players.”
Bayern Munich striker Lewandowski echoed Mbappe’s concerns over the demands on players if a World Cup was held on a biennial basis, with both speaking at the Globe Soccer Awards.
“We have so many games every year, so many tough weeks, not only the games but preparation for the season, preparation for the big tournaments,” said the 33-year-old.
“If you want to offer something special, something different, we also need a break.
“If we have a World Cup every two years, the expectation is the time where footballers play at a high level will go down … It is physically and mentally impossible.”
