"The woman said because I wear a turban, there was no need for me to waste my time going for the interview," he said.
But general manager Mike Rutherford told the Herald there was no turban ban at First Security and the email "was the result of a misunderstanding by the person who authored the correspondence".
"We employ quite a number of officers who are from the Sikh community and they wear their turban whilst on duty on a daily basis," he said.
"The only request that we have of these officers is that the turban be either black or dark blue in line with our uniform colours."
Mr Rutherford has also emailed an apology to the Sikh Council.
"I sincerely apologise if this has caused any member of the Sikh community any concern or distress."
He told the council he would now "personally shepherd" affected candidates through the recruitment process. Verpal Singh, secretary of the Sikh Council, said the turban was an important part of the Sikh faith and many practising Sikhs worked with the police and air force without any issues over turbans.
The Human Rights Commission said banning turbans would be potentially unlawful.