A discussion within the ACCM (Advisory Committee on Complementary Medicines) used krill oil as an example. The compositional guideline was drawn up by the TGA in conjunction with the applicant to reflect the nature of their substance. However other suppliers (not the original applicants on the "new substance application") provide krill oil substances which vary from these guidelines.
The ACCM discussed efficacy and dosage, differences in the compositional guidelines, natural substance variation and differentiation, the potential USP monograph, and lack of any serious safety concerns. This highlights the difficulty that arises when one supplier funds an application to have a "new substance" approved (commonly costs around $40,000) only to see other suppliers insist that the approval extends to their substances as well. A sponsor of a product can use a krill oil that is not compliant with the compositional guideline, but the TGA can still ask for safety data if they have any concern over the substance. Read here