You will need this approval if you intend to use a method of segregating during transport road that does not comply with the Australian Code for the Transport of Dangerous Goods (ADG Code).
Segregation involves separating dangerous goods from incompatible substances. This minimises the risk of contamination and / or dangerous reactions if they came into contact. Contact could be caused by a leak, spill or vehicle accident.
The agency recommends that you contact them before submitting an application.