The South African delegation is being led by Justice Minister Ronald Lamola and will be joined by senior political figures from progressive political parties and movements across the globe.
Thursday's hearing is set to last three hours and will be followed by Israel's arguments in its defense the next day.
Susan said that at the ICJ, gathering evidence against Israel would be critical, stating: "In my mind, that will not be difficult, as there are over 2 million eyewitnesses to what Israel has done and is doing in Gaza."
However, she stressed that the biggest "challenge" would be ensuring the "safety of witnesses and their ability to present their testimony."
"That is going to be another and more complicated matter. So, for example, some of the main currently available witnesses will be doctors, journalists, humanitarian workers. But we know, for example, that many journalists have been killed and even possibly directly targeted," she added.
Noting that testimonies could also be submitted directly to the case online, Susan said technology "may well help to make witness statements more available."
South Africa asks Israel to take 'effective measures' to ensure preservation of evidence related to allegations of genocidal act.