FIFA's medical chief will tell next month's landmark meeting to decide on the 2022 World Cup in Qatar that the tournament must be moved to the winter to protect the fans.
Michel D'Hooghe, the chairman of FIFA 's medical committee, will advise the executive committee that the risks of hundreds of thousands of supporters moving between venues in the extreme heat are too great.
The committee is now expected to agree in principle to move the World Cup to the winter, most likely in November/December 2022, and then embark on a six-month exercise to hammer out how it will affect the international calendar and the domestic leagues.
D'Hooghe's comments came as the United States' FIFA member Sunil Gulati said he was prepared to "rock the boat" and demand more time before making a decision.
But as the world governing body's medical chief, D'Hooghe's strong report favouring a move will make a significant impact.
D'Hooghe told Press Association Sport: "My position is very clear. From the medical point of view I think it will be better not to play during the hot summer months.
"I am sure the Qataris could organise it when they have such technical skill, and I know they could play and train in a stable, acceptable temperature.
"But the World Cup is more than about games and players - I have done eight World Cups so I know a bit about it.
"A World Cup is about the 32 delegations, it's about the whole FIFA family and the 12,000-15,000 media working very hard, and most importantly it's about the fans.
"They will need to travel from venue to venue and I think it's not a good idea for them to do that in temperatures of 47 degrees or more."