Noel Cantwell Dies
Cantwell also managed Coventry City and Peterborough United when he hung his playing boots up and also represented Ireland at cricket.
"Noel Cantwell was one of the great characters not only of football but of Irish sport in general," said Ireland FA chief executive John Delaney.
"He was a great inspiration to those who played alongside him whether for club or country.
"On behalf of the FAI and the family of football in Ireland I extend sincere sympathy to Noel's family and friends."
Manchester United will hold a minute's silence before Saturday's game with Manchester City as a mark of respect.