A New Zealand rugby player who had wanted his brain to be studied after suffering from the effects of multiple concussions has died aged 39, police said on Wednesday.

Shane Christie, a former Maori All Blacks player, had campaigned for greater awareness in rugby of the impact of repeated blows to the head.

After retiring from the game in 2017 Christie reportedly suffered from headaches, memory lapses, speech problems, depression and mood swings consistent with chronic traumatic encephalopathy (CTE).

Local media said the death of Christie, who also played for Otago Highlanders, Canterbury Crusaders and the All Blacks sevens team, may have been suicide.

“The death will be referred to the coroner and we have no further information or comment we can provide,” said police.

New Zealand Rugby said Christie was deeply passionate about the sport and would be “remembered always”.

Christie reportedly wanted to donate his brain to the New Zealand sports human brain bank for its studies into CTE, a degenerative disease caused by repetitive head trauma that cannot be detected in living people.

Hundreds of American football (NFL) players have been affected by the condition, which is linked to an array of behavioural symptoms including depression.

CTE has been cited in a number of violent deaths involving former NFL players.

A 2023 study by the Boston University CTE Center said that of 376 brains of former NFL players, 345 of them were found to have CTE.