Should I disclose in the interview that I am transgender?
In most cases it is solely your decision whether you wish to disclose that you are transgender, as your sex or gender identity has no bearing on your ability to do the job. There are some very limited circumstances where it is legal to employ only a woman or a man for a particular position, i.e. being female or male is a genuine occupational qualification. In these limited situations, some transgender people may need to provide evidence about their sex.
Am I able to ask a transgender job applicant for any previous name, in order to verify identity?
If previous name details are required from all applicants, for a specific purpose, then you can ask a transgender applicant to provide the details. As disclosure of the information might have significant additional implications for a transgender job applicant, reassurance should be given that the information will only be used to verify identity and not for any other purpose.
It would be discriminatory to ask a transgender person to provide details of their previous name if this information was not required from other job applicants. Discrimination against transgender people comes under the ground of sex in the Act.
Information about human rights and transgender/trans people can be found at: http://www.hrc.co.nz/transgenderinquiry