Former marathon queen Allison Roe is concerned for the future of women's sport as debate on the inclusion of transgender athletes grows.
The 1981 NZ Sportsperson of the Year is one of 41 former Olympians and world-class athletes, who have penned a letter to the Government in response to Sport NZ's draft proposal on ways to allow trans women to compete against other women at club and community level.
Roe, a former New York and Boston marathon winner, believes the impact of allowing "biological men" to compete against women will be detrimental to the sporting aspirations of young female athletes.
Speaking to The AM Show, Roe says there needs to be a much wider discussion, and has called on Sport NZ and the Government to include as many women as possible in the proposal.
"Quite frankly, there hasn't been very much consultation," Roe says. "It's very narrow and I believe it's very important that they ask the women.
"Women have not been asked and we make up more than 50 percent of the population.
"At the highest level, it is impossible to compete with. As women, we have had a real struggle through the last 50 years, even having our own sports and having women participate in sports.
"This would be a huge retrograde step in my view."
Sports Minister Grant Robertson has told The AM Show the discussion document is still in its infancy.
Robertson says the starting point of the debate is every New Zealander has the right to participate in community sport and where it goes from there is part of the consultation process.
"It is a consultation, so we do want to hear from all sorts of people, but our starting point is that all Kiwis have the right to participate," Robertson says.
"The second side of the question is around what happens at the elite level, and there we are guided by international federations and the rules that they have.
"That is an evolving area, but I don't think you would want politicians deciding who exactly can compete in elite events.
"I back what Sport NZ is doing, because sport is so intrinsic to what we are as people.
"This isn't easy. I know there are many voices here, so let's start from the premise that we want everyone to be involved in sport and go from there."
Former Commonwealth Games gold medal-winning swimmer Dave Gerrard says the fundamental issue is the biological differences between men and women - even in a fully transitioned female athlete.
Gerrard - a sports medicine specialist - says the "playing field won't be level" and science backs that opinion.
"Biologically, they are not [a woman]," Gerrard tells The AM Show.
"Yes, you have transitioned, but you are still biologically a male, with the benefits that have accrued through the post-pubertal effects of testosterone.
"There is nothing magic about that - it's science and physiology - it's been well and truly explored through literature, so the evidence is there.
"There is no easy and quick answer, but we have been down this path similarly before.
"In the 1980s, the East German female athletes were pumped full of anabolic steroids, we had the Chinese swimmers of the 1990s and, more recently, the Russians, who have benefited from systemic steroid doping.
"It's the same as allowing a transgender female to compete, who would have 10 times the level of testosterone in her body than her competitors that she is beating."
Roe agrees, saying men are physically faster and stronger than women and her concern is participation numbers in women's sport will drop off considerably in the coming years.
"As an athlete myself, I ask if our daughters, our granddaughters and their daughters - do they ever make a team again if we have biological men competing at the highest level.
"Our daughters could miss out on sporting scholarships or could miss out on a podium or could miss out on representing their country at the Olympic games.
"Everyone has the right to participate and compete in sport in this country - no matter who they are - that is a given. It's a matter of finding a way and possibly the way forward is transgender athletes are able to have their own category."
The high-powered group of 41 includes Roe, Gerrard, All Blacks great Jeff Wilson, Olympians Danyon Loader and Barbara Kendall and running legend Anne Audain.