FIFA has told Morocco it does not want "white elephant" stadiums to be built after the Moroccans questioned the bidding process to host the 2026 World Cup.
Morocco wrote to FIFA president Gianni Infantino to question its demands for technical criteria as part of the process.
It is competing with a bid from the United States, Mexico and Canada, with the North American bid having the existing infrastructure to stage what will be the first World Cup with an expanded 48-team field.
Morocco would need to either build or renovate 14 stadiums, along with other infrastructure, in a multi-billion dollar project.
"In order to avoid unsustainable bids ... with the creation of 'white elephants' -- something FIFA has been heavily criticised for in the past -- the scoring system evaluates with objective criteria how meaningful and sustainable is the infrastructure presented in the bids," FIFA said in a statement to the Associated Press.
Bids to stage the tournament could be ruled out before FIFA's Congress votes on the issue in June if they receive low scores from a task force.
But Morocco Football Federation (FRMF) president Fouzi Lekjaa wrote to Infantino to say details of the scoring system were received only two days before the March deadline to receive bid books.
The North American bid said those details had reached it at the same time.
"As a matter of principle, the basis of the preparation of a bid should not be the scoring system for the technical evaluation but rather the requirements which FIFA has provided to the bidders in 2017 through the bidding and hosting requirements," FIFA said.
"Contrary to what the FRMF implies, the hosting requirements, which were clearly set in the bidding registration and other bidding/hosting documents provided in 2017, have not changed.
"The scoring system merely provides a methodology for evaluating and documenting the extent to which the bids submitted fulfil those requirements in certain key areas."
Morocco bid officials also voiced concern about criteria including that the population of host cities must be at least 25,000, but FIFA said a bidder would not be ruled out if scored poorly on those areas.
"As explained many times, the bidding process for the 2026 FIFA World Cup has been designed to evaluate the bids against objective criteria and so avoid a return to the secret and subjective decisions of the past," the governing body added.