RG146 stands for Regulatory Guide 146. Created by ASIC, it is a financial regulation for anyone providing financial advice. It is documented and explained in ASIC's Regulatory Guide 146 Licensing: Training of financial product advisers.
ASIC specifies in RG146.4 that "all natural persons who provide financial product advice to retail clients must meet the training standards (unless they fall within certain limited exemptions)."
As such, current or potential advisers who will be providing retail financial product advice require an appropriate set of knowledge and skills in order to be able to apply their knowledge in specific practical situations. ASIC has set out a range of training standards that need to be satisfied by advisers which can be referred to on RG146.6 and RG146.7.
Source: Australian Securities and Investments Commission (July 2012), Regulatory Guide 146: Licensing: Training of financial product advisers (PDF), Australian Securities and Investments Commission, p. 4, archived from the original (PDF).