The candidate was qualified to fill the role of women's officer at a university student union.

With one exception: he is a man.

James Ritchie has resigned from the position at the Tasmanian University Union following mounting opposition and an online petition.

He had been voted into the position with a clear majority over a female candidate more than three weeks ago.

"There has been a lot of public pressure for me to resign, a lot of interest groups that want me to resign," Mr Ritchie told ABC radio.

"But the main thing for me was I felt my ability to be effective in the role was now diminished and that's the most fundamental thing."

Opponents had launched a petition on the website change.org to have Mr Ritchie removed from his role in the TUU.

The petition said Mr Ritchie "was elected to the role of women's officer unconstitutionally and unethically and yet the TUU staff refuses to disqualify his candidacy".

However, TUU guidelines did not state a preferred gender for the role, saying only that "an interest in higher education and student issues would be advantageous".

The state's anti-discrimination commissioner, Robin Banks, also said there was no legal reason why a man could not occupy the role of women's officer.

Mr Ritchie said: "In my opinion, it's irrelevant if (the position is) held by a female or a male. In this election I believe I was the best person for the role.

"If you can't get a society where women feel they can approach men about a number of issues and men feel they can approach women about a number of issues, how do you really make progress?"

The student union has now introduced a requirement that candidates sign a statutory declaration confirming they identify as female.