Pep Guardiola's Manchester City are the Club World Cup holders
It comes after players' union Fifpro and the WLA called on Fifa to reschedule the tournament, due to take place next summer, amid a threat of legal action.
Fifpro and the WLA said "players are being pushed beyond their limits".
In a letter sent to Fifpro and the WLA, which has been seen by BBC Sport, Fifa says it has "a duty and responsibility" to implement an international match calendar in the "best interests of world football".
Fifa insisted Fifpro and the WLA were consulted about changes to the overall 2025-30 international match calendar, including the 2025 Club World Cup, which was confirmed by the Fifa Council in December 2022.
Although it says it is open to talks, Fifa has no intention of altering next year’s Club World Cup, saying it is "fully within our rights to set the parameters of our competitions whilst respecting the regulatory framework in place".
Manchester City and Chelsea are among the 12 European representatives at the expanded Club World Cup, to be held in the USA between 13 June and 15 July 2025.
Fifa point out that domestic member leagues of the WLA, such as the Premier League, can arrange their own competitions, noting the organisation of "international tours" in recent years.
Last summer, the Premier League hosted a six-team summer series in the USA, involving Chelsea, Newcastle, Brighton, Fulham, Aston Villa and Brentford.
Fifa also asked if Fifpro and the WLA had been in touch with other bodies, given their games "are responsible for a fractional amount of the total elite club games around the world".
“While we disagree with the tenor and content of your letter, we have nonetheless taken note of your concerns and are more than happy to invite you to discuss the matter further at a time convenient to you," Fifa added.
--- Courtesy of BBC Sport