Chapter 4
Cooperation with and assistence to Court in or outside South Africa
Part 2
Judicial assistance to court (ss 14-32)
14 Areas of cooperation and judicial assistance
The relevant competent authorities in the Republic must, subject to the domestic law of the Republic and the Statute, cooperate with, and render assistance to, the Court in relation to investigations and prosecutions in the following areas:
(e) facilitating the voluntary appearance of persons as witnesses or experts before the Court
Facilitating voluntary appearance of persons - national procedures for ICC proceedings
EDIT.