Researchers say each year, the issue of participation sparks debate and accusations of discrimination. The fear is prosthetics and hearing aids potentially harm the wearer and other players coming into contact with the equipment.
Prosthetic devices were deemed unsafe. Recent improvements have included the ability to swivel ankles and knees for lateral movement, as well as adjusting arms to better grip the ball for passing, lineout throws and kicking preparation.
Research also identified custom-made hearing aids had the best comfort and safety characteristics during running and tackling.
Patria Hume, a former New Zealand rhythmic gymnast and now professor at the Auckland University of Technology, has been working on the projects with the IRB.
"Changes in technology are allowing us to make contact sport more inclusive. With softer materials and the ability to customise hearing aids and prosthetics, those with impairments can be integrated into mainstream sport.
"As a biomechanist, I can't help but analyse people when they're walking down the street or sitting at their desks. I look at young kids and think 'you could be a netballer' or 'don't sit like that, you'll get a back injury'," Hume says, laughing.
Cost is also a significant factor in the IRB assessment.
"We want a hearing aid that's more like a disposable contact lens; a cheap but effective option which makes it accessible," Hume says.
"Hearing-impaired rugby players can pay several thousand dollars for hearing aids that are shock or water-resistant but they don't want to wear them [on the rugby field] in case of damage.
"The prosthetics allow the amputees to move more freely. A key factor in rugby is the ability to change direction. Sprinting in a straight line is a lot easier. New technology will have modifiable ankle and knee joints. The arms will also have a detachable device enabling better grip of the ball."
The IRB is considering the prosthetics proposal. If approval is granted, Australian, German and South African scientists will collaborate with Hume and her New Zealand colleagues to further develop upper and lower limb prototypes.
League, hockey, netball and football have also indicated an interest in using the technology. Former Kiwi Tawera Nikau has played the odd game of league since his right leg was amputated after a motorcycle accident in 2003.
"This sounds innovative and inclusive but I also think you might need some rules regarding protection, as a duty of care to other players. I know players who have worn [prosthetic limbs] in games at a reasonable level with full-on contact. They were fully bandaged up and no one knew or asked any questions."
England Rugby World Cup winner Ben Cohen is an advocate for deaf players and hearing aid use. He was diagnosed with about 30 per cent hearing loss as early as 2003.
"I was in denial about it and I thought, 'I'm not going to let it affect what I am doing'," Cohen told the Mirror in October.
However, it became clear it was a problem.
"Before the World Cup final, I was in the changing room, reading a newspaper article about the team, and our coach Clive Woodward was due to give his inspirational pregame chat. I was so distracted by the article that I hadn't even heard my team-mates leave the room and so I missed it."
