"I personally think that, in the end, the 2022 World Cup will not take place in Qatar," he said, citing the region's sweltering summer climate.
"Medics say that they cannot accept responsibility with a World Cup taking place under these conditions."
Qatar organizers, who won the right to host the tournament in 2010, claim the intense heat, routinely rising above 40 Celsius, will not be a problem because of the cooling technologies it plans to employed in stadiums, training areas and fan zones, there is still widespread concern over the health of the players and visiting supporters.
"They may be able to cool the stadiums," Zwanziger countered, "but a World Cup does not take place only there. Fans from around the world will be coming and travelling in this heat and the first life-threatening case will trigger an investigation by a state prosecutor.
"That is not something that FIFA ex-co members want to answer for."
FIFA spokesperson Delia Fischer said Zwanziger's comments do not necessarily reflect those of the executive committee.
"He is expressing a personal opinion and he explicitly says so," Fischer said. "We will not comment on a personal opinion."
FIFA president Sepp Blatter, in May, called the selection of Qatar as tournament host "a mistake."
"The Qatar technical report indicated clearly that it is too hot in summer, but the executive committee with quite a big majority decided all the same that the tournament would be in Qatar," Blatter told told Swiss television station RTS.
FIFA reportedly is considering moving the World Cup to January/February 2022 or November/December 2022, but that would disrupt domestic league schedules.
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