"This is a recipe for disaster in mass gatherings," Haghani said, adding that it was "reminiscent" of the 2010 Love Parade in Germany but with "far many more casualties".
During that free-access music festival, 21 people died from suffocation and hundreds more were injured as the crowd struggled to escape a ramp leading to the event.
Such incidents are frequently caused by "mismanagement by event or venue organisers" rather than "panic" among the crowd, said John Drury, an expert on crowd psychology at the University of Sussex.
In Itaewon on Saturday, witnesses told AFP that early on in the night partygoers along one particular chokepoint were sustaining injuries simply due to crowd density.
Less than two hours later, people began spontaneously falling over and then trampling on each other in a tight knot of bodies that made it all but impossible to move or breathe.
To avoid too many bodies being crushed in too narrow of a space, such street events need "months of planning" by experts, Kant in the Netherlands said.
This includes calculating visitor capacity beforehand and then counting and monitoring the size of the crowd and possible bottlenecks either on the ground or via CCTV.
"During the event, if maximum capacity is reached, further access to that area should effectively be shut off," Kant added.
It was only around 2:00 am, or more than seven hours after the first emergency call, that officials banned anyone except officials and medical workers from entering Itaewon.
National police chief Yoon Hee-keun acknowledged that officers had failed to properly responded to the many citizen calls warning of danger, while the interior minister promised an investigation into what exactly happened in Seoul.
"I am 100 percent convinced this tragedy was preventable," said Kant.
"Crowd crushes or crowd disasters were and are always predictable, thus preventable."
