Tax Practitioners Board (TPB) The TPB is responsible for the administration of the Tax Agent Services Act 2009 (TASA) and the registration and regulation of tax practitioners. These include tax agents and business activity statement (BAS) agents. The TPB also has the responsibility to deter the use and activities of unregistered preparers. The TPB's functions and powers are defined in the TASA and they are supported by staff made available by the Commissioner of Taxation. The TPB's role is to ensure that tax practitioner services are provided to the public in accordance with appropriate standards of professional and ethical conduct