On Tuesday, world football's governing body confirmed that the proposals had been given the go ahead, with the tournament set to be increased from the 32 countries who will take part in 2018 and 2022, using a format of 16 groups of three teams.
Last month, the European Club Association (ECA) - of which the likes of Barcelona, Real Madrid, Bayern Munich and Manchester United are all members - expressed its opposition to the plans.
Now that the FIFA Council has voted in favour of the proposals, the ECA has released a statement questioning the motives for the decision, as well as the speed in which it has been made.
"The European Club Association reiterates that it is in principle not in favour of an expanded World Cup," the statement read.
"We fail to see the merits to changing the current format of 32 that has proven to be the perfect formula from all perspectives.
"Questionable is also the urgency in reaching such an important decision, with nine years to go until it becomes applicable, without the proper involvement of stakeholders who will be impacted by this change.
"We understand that this decision has been taken based on political reasons rather than sporting ones and under considerable political pressure, something ECA believes is regrettable.
"ECA will analyse in detail the impact and the consequences of the new format and will address the matter at the next meeting of its Executive Board scheduled for the end of January."