Vocabulary choices (dropping a "g", adding a "k", or using the personal pronoun "youse" in mixed company), suburb of residence, and the schools or universities attended, still play an undetected role in candidate selection, said Anita Ziemer, managing director of Slade Group.

This is particularly true for entry- to mid-level roles, and privately owned professional firms are often the biggest offenders disguising social discrimination as finding the right "cultural fit" for their business.

"There is a lot of evidence that defines the attributes of top performers in any work setting, yet nowhere does it talk about your suburb, the school you went to, or whether you speak the Queen's English," Ziemer said.

"Unfortunately there is an unspoken barrier erected by potential employers, which is still present in today's working society, particularly in areas such as law, finance and consulting."

"Perception psychology" can occur at every hiring touch point, according to Ziemer, from the recruiter to the HR person in the employing organisation, to the line manager ultimately hiring the candidate.

"It's more common for entry level and second and third role professional opportunities. It's a lot less relevant the higher up the organisation a person is, because (and fairly) their work history and reputation speaks for itself," she said.

"Where the selection decisions are made with an open mind and early on in the hiring process, the chances for an equitable outcome increases dramatically," she said.

Slade Group cited examples where in Melbourne they want to know whether you went to "Melbourne" or "Monash" and in Sydney a "nice eastern suburbs girl" was wanted. In one case a client eliminated a high performing financial advisor as a candidate, because he referred to "youse" mid-discussion.