Sometimes States voluntarily hand over responsibilities to the Commonwealth. Under Section 51 (xxxvii) of the Constitution any State or States may ask the Commonwealth Government to be responsible for certain areas. This is known as the 'referral power'.
It means that the Commonwealth has the power to make laws if the State (or States) refers that matter to them or hands over those powers to the Commonwealth. In 1977, the South Australian and Tasmanian governments transferred ownership and control of their country railway systems and, in 1996; The Kennett government in Victoria handed over arbitration power to the Commonwealth.
It means also that the States can cooperatively enact identical legislation to the Commonwealth to set uniform standards. This is how the Commonwealth has achieved uniform standards in the offshore oil industry and air safety regulations.
The power of referral has been used on several occasions, but State governments are naturally unwilling to hand powers to the Commonwealth.