Green MP Golriz Ghahraman says it is "absolutely offensive" to be called a genocide-denier, and insists she has not misled the public over defending people accused of genocide in Rwanda.
But she admits that her profile page on the Green Party website, which states that she has put African leaders on trial for abusing their power, "could be clearer".
In a series of tweets today, former Labour staffer Phil Quin criticised Ghahraman's work at the Rwanda Tribunal, saying she defended "the worst killers known to man" and calling her a genocide-denier.
"Any MP who acted as a voluntary intern to defend war criminals, and authors papers that deny the Rwandan genocide, must resign," said Quin, who lived and worked in Rwanda for several years.
"Call me old fashioned, but I think volunteering as a 'life changing experience' to defend mass murderers (who had the priciest lawyers in the business) should disqualify one from becoming a member of the NZ Parliament," he said in another tweet.
The posts raised questions about whether Ghahraman had misled the public into believing that she had prosecuted those responsible for genocide in Rwanda, when she had in fact been part of defence teams.
Her profile page on the Green party website says: "Golriz has lived and worked in Africa, The Hague and Cambodia, putting on trial world leaders for abusing their power."
Ghahraman admitted that her profile page, which she didn't write, "could be clearer, but it's certainly not false".
But she said she has never hid her defence work, that it's "certainly not something I'm ashamed of", and that international criminal justice needs both the defence and the prosecution to work well to ensure a robust system.
"It's absolutely offensive to say that I deny genocide, because there's nothing that's been more important to me than to highlight genocide as an international crime.
"The reason we have these trials is to say that genocide is not okay. But that we want it dealt with in a human rights-based process, a fair process that includes a defence and a prosecution and judges and proper investigation."
She said that she worked as an unpaid intern as part of a team that defended Joseph Nzirorera, who died before he could be convicted of genocide, and in a paid position as part of a team representing pop singer Simon Bikindi, who was convicted for incitement to genocide.
She also worked on the pre-trial of Bosnian Serb wartime leader Radovan Karadžić, who was found guilty of genocide and crimes against humanity.
She worked on the prosecution at the Khmer Rouge Tribunal.
Quin later tweeted that he did not care whether Ghahraman misled the public, but he did care that she defended people in the Rwanda Tribunal in the first place.
Ghahraman said she has never met Quin, but that his comments showed "an embarrassing lapse in understanding".
"No one is saying there is no such thing as genocide. It's like saying a defence lawyer [defending someone charged with murder] in our justice system here is a murder-denier.
"My CV is on LinkedIn. It's certainly not something I'm ashamed of. It's the human rights model. We have to work on both sides."