Wigs and robes originated in England as a way to distinguish defence lawyers from other members of society. In NSW courtrooms, such as the District Court, it represents to the public and jury that all parties are equal and therefore they look the same. No discrimination, only judgment on the evidence presented.
Barristers in Sydney District, Supreme and High Courts are required to wear wigs, robes, jackets and jabot, while their instructing solicitors car wear dark formal attire.
In the Downing Centre Local Court, Bankstown Local Court, or Parramatta Local Court in Sydney, you wont see any wigs or robes being worn as it is not a requirement in the NSW Local Court.