A controversial feminist group marked Transgender Awareness Week this year by flying over an anti-trans activist from Canada.
Meghan Murphy is a radical feminist who believes transgender women aren't women - views that have seen her banned from Twitter.
She was the star guest at Feminism 2020 on Friday - an event organised by Speak Up For Women that was originally going to be hosted at Massey University, but cancelled before being picked up by ACT leader David Seymour and hosted at Parliament.
Murphy told Newshub Nation on Saturday her position was "pretty straightforward".
"I don't believe that it's possible to change biological sex, so I think that you're born either male or female, and you remain male or female for life.
"Being a woman isn't a feeling - it's a fact. I guess I don't quite understand what the purpose is in identifying the opposite sex."
Murphy said she has concerns about "women's rights as a whole", but added she feels "total empathy" towards people with gender dysphoria, mental illness and their identities.
"The problem with trans is there's no definition of transgender - it's just an announcement," she told Newshub Nation. "There's no way to discern who is transgender. It's just something that you say."
Agender NZ, an organisation which supports transgender people and their families, described Murphy's "repellent" comments as "US Trumpian-inspired rhetoric".
"My reading of current social media is that the views of Ms Murphy and Speak Up For Women are not getting much traction in our society where we have a broad inclusive view of human gender identity and expression," president Tracee Nelley said.
"Human sexual biology is more diverse than a simple binary male and female.
"New Zealand has increasingly celebrated sexual and gender diversity, moving beyond the fear mongering and divisive comments espoused by Speak Up For Women."
Agender was invited to debate Murphy on Newshub Nation, but was unable to arrange someone in time.