Sex discrimination commissioner slams gender definition proposal

Alison Penfold put forward a private member's bill to change the legal definition of a man and woman. (Supplied: Alison Penfold)

Australia's sex discrimination commissioner has criticised proposed changes to the Sex Discrimination Act which would change the legal definition of a man and woman to be defined purely by sex.

Nationals MP Alison Penfold put forward a private member's bill and petition to change the act, which she said strips the rights of biological females in women-only spaces.

LGBTQI+ groups warn the proposed change would undo decades of advocacy work and protections for gender diverse Australians.

Australia's sex discrimination commissioner has condemned a bill seeking to change the Sex Discrimination Act, fearing it would erode the rights of all women while harming the LGBTQI+ community.

Commissioner Dr Anna Cody said her office was not consulted on the private members' bill from Alison Penfold, the federal member for Lyne and Nationals MP.

It aims to change the legal definition of a man and woman as defined purely by biological sex.

It could restrict trans women from accessing female-only spaces like bathrooms, change rooms, gyms, sporting groups and prisons.

Dr Anna Cody says women have fought for decades not to be defined by their biological sex. (Supplied: Dr Anna Cody)

"The women's movement has fought for centuries to avoid being defined only by biology," she said.

"We know that being a woman has many aspects to it, and that biological aspect is one part of it, but not the entirety of it."

Dr Cody said the bill created "false competition" between women's and trans rights, while harming one of Australia's most vulnerable communities.

"It sends a strong message to a tiny, marginalised, disadvantaged community which is less than one per cent of the population that they're not welcome, their needs aren't important, and that their right to be welcome and included in society is not being respected," Dr Cody said.

Ms Penfold's bill comes after Giggle for Girls founder Sall Grover lost her appeal against trans woman Roxanne Tickle in the federal court. The court found that Ms Grover had discriminated against Ms Tickle by banning her from the women-only app.

Ms Penfold said the case highlighted the need to protect the rights of "biological women". The issue was brought to her three years ago by anti-trans activist Kirralie Smith, also from her northern New South Wales electorate.

"The court now has to interpret whether sex or gender identity prevails where there is a conflict," Ms Penfold said.

Ms Penfold says the Tickle v Gig