A lawyer says All Blacks are among hundreds of former players taking legal action against World Rugby over a failure to protect them adequately from the risk of brain damage.
The players say rugby authorities failed in their duty of care over a period of several decades and are seeking a group litigation order at the London High Court on Saturday for claims against World Rugby, the England-based Rugby Football Union and the Welsh Rugby Union.
Former All Black Carl Hayman, 44, has been diagnosed with early-onset dementia and probable chronic traumatic encephalopathy and has previously confirmed he is among the 295 former rugby players being represented by British law firm Rylands Garth.
Lawyer Richard Boardman, who is leading the legal action, told RNZ's Nine to Noon Hayman was not the only New Zealander involved.
"It's about half a dozen, with several of those having played for the All Blacks, I believe," he said.
"(But) a lot of our claimants are applying for anonimity so we must respect that."
Boardman said thousands of pages of medical evidence had been collated, with more than 40 allegations lodged of systemic failings in relation to removal from play, stand-down periods and multiple concussions, which have allegedly led to conditions such as motor neurone disease and dementia.
"Our allegation is that the sports' governing bodies - that is those at the top of the pyramid - had a duty of care towards their rugby-playing community and they're in breach of that duty in a negligent manner, not just in respect of a single game but in respect of systemic failings across the entire sport," said Boardman, who said the players would be seeking financial reparation.
"We've got dozens of players who are struggling even to hold down a part-time job and they need looking after.
"It's about damages so they can look after themselves and their families. Nobody signs up for a sport to get permanent brain damage.
"And this is about getting the issue out there, into the public arena, to help protect current and future players."
Boardman confirmed about 150 former rugby league players and 25 football players were also part of the legal action.
Former Welsh international Alix Popham who played for Wales between 2003 and 2008 and is regularly in contact with Hayman, revealed a growing number of New Zealanders were becoming aware of the issue.
Former Wales rugby player Alix Popham. Photo: Fotosport
"There's quite a few players from New Zealand, not just Carl unfortunately. And this number is growing daily," Popham said, recalling the unregulated early days of his profesional career.
"It was like the wild west, there was no medical care out on the training pitch, the training would last for 2-3 hours," he said.
"It was unbelievable, if you felt dazed, you would take a squirt of water to the face, some salts and were expected to carry on. Unless your leg was hanging off, you had to get back into the defensive line.
"The 15 who were still playing at the end of the week would play on Saturday. It would be that mentality."
Formal proceedings in the case were opened at the High Court in London on June 23.
World Rugby has taken several steps to mitigate the impact of concussion including introducing smart mouthguard technology for head impact assessment and starting trials to lower tackle height in community rugby.
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