With recent changes to the Working Holiday Makers legislation(or Backpackers tax) passing parliament, in addition to taxing overseas employees at 15% as of the 1st January 2017, the employer is required to be registered as employing oversea workers.
Below are two links, one to register and another to assist in ensuring the employee is eligible and working under the correct Visa.
Employer Reg: https://www.ato.gov.au/twhm/
The registration is due by 31st January 2017. More information can be found on the ATO website at: