A United Nations expert has blasted Australia's Sex Discrimination Commissioner Dr Anna Cody's position as 'flawed' after she said transgender women are covered by breastfeeding discrimination protections.

The row erupted on Monday night when Dr Cody appeared before a Senate committee and faced questioning from Liberal senator Leah Blyth about the scope of the Sex Discrimination Act.

Senator Blyth referenced Section 7AA of the Act, which prohibits discrimination on grounds of breastfeeding, noting the explanatory memorandum stated the provisions were intended to protect women who breastfeed.

'Does the commission interpret Section 7AA as providing breastfeeding discrimination protections to a biological male who identifies as a woman and induces lactation?' Senator Blyth asked.

'Yes, Senator,' Dr Cody replied.

On Tuesday, UN special rapporteur on Violence against Women and Girls Reem Alsalem entered the debate, accusing Dr Cody of overlooking the material reality of biological sex.

'The position of the Sex Discrimination Commissioner should not come as a surprise and in fact is the only position that she can take in order to try be consistent and coherent to herself and others given her overarching views and opinions,' Alsalem wrote on X.

She argued that Dr Cody's position was rooted in conflating sex and gender identity.

'We must understand that the position she expressed is the only position one can organically arrive at if one conflates sex and gender identity, disregards the material reality of women in favour of women being a feeling or an identity, and disregards that certain reproductive processes are tied to being of a certain sex,' she said.

Alsalem said she had previously tried to debate the issue with Dr Cody but had been unable to bridge what she described as a fundamental philosophical divide.

'There is one point where we fundamentally differ and that I think underpins her positions on this,' she said.

'Commissioner Cody believes that if we were to recognise that women and girls have historically been discriminated against based on their sex, that would mean that we accept that this discrimination is biologically determined and that this discrimination is acceptable or justified.'

Alsalem called Dr Cody's position 'flawed'.

'We would not follow the same logic with any other form of discrimination, say for example racial discrimination,' she said.

'Naming that black people are often and have been often discriminated against because they are black does not suggest that such discrimination is justified, nor a tacit acceptance of it.

'The answer to a serious problem cannot be to stop naming the cause, in the hope that this cause would magically go away or that its impact on the lives of people would soften or vanish.'

The Senate hearing also examined workplace rights for transgender women who medically induce lactation.

Referencing concerns from an Australian Human Rights Commission report, Senator Blyth asked if employers could be required to provide lactation breaks and breastfeeding facilities to a biological male who had induced lactation.

'They are subject to the same protections as anyone who is breastfeeding,' Dr Cody replied.

The commissioner was also asked if a recent New South Wales government decision to restore references to 'women' and 'mother' in breastfeeding policies in the NSW Parliament aligned with the commission's guidance, after they were controversially removed, sparking outrage from NSW Opposition Leader Kellie Sloane. 

NSW Premier Chris Minns later intervened to reverse the decision.  

Dr Cody said she would take that question on notice.