According to the Victorian Government Solicitor's Office, a suppression order is a directive given by a court to ban or restrict the publication of details of a court case.
Some of the reasons a judge might issue a suppression order include:
to protect the proper administration of justice
to avoid prejudicing the interests of national or international security
to protect someone's safety
and to avoid causing undue stress to a complainant or witness, particularly in sexual or family violence cases.