Former North Melbourne player Red Og Murphy has passed away aged 21 in Ireland.

Murphy, who spent 2019 on North Melbourne's list as a Category B rookie, returned to Ireland after 12 VFL games with the club, citing his desire to return to Gaelic football.

North Melbourne CEO Ben Amarfio expressed his sympathies to Murphy's family in a statement on Saturday.

"On behalf of everyone at the club, I would like to pass on my deepest sympathies to the Murphy family at this difficult time," Amarfio said.

"Our thoughts are with those closest to Red Og, his family and friends in his home in Ireland, and all those who played and worked alongside him and became friends with him during his time at North Melbourne."

Upon his return to Ireland Murphy starred for local Gaelic side Sligo across 2020 and 2021, featuring in all league and championship games.

Throughout 2022, Murphy opted to play for Dublin City University's team, where he was studying to be a teacher.

Local authorities are yet to confirm the cause of death.

North Melbourne will wear black armbands in their match against Brisbane at the Gabba on Saturday night in honour of Murphy.