Appointment of tax officers: Government may notify specified classes and deem Central Excise officers to serve under GST. Section 3 vests the Government with the power to appoint by notification specified classes of officers for administration of the Act, enumerating graded categories from Principal Chief Commissioners/Principal Directors General down to Assistant Commissioners/Assistant Directors and any other classes as deemed fit; a proviso deems officers appointed under the Central Excise Act, 1944 to be officers under this Act to ensure continuity.