The giant lock - who measured in at 6ft 5in and 20 stone during his playing career - made his international debut in Paris in 1974 and went on to become a stalwart of the second row for the next decade.
Munster legend Keane, who also represented the British & Irish Lions on the 1977 tour to New Zealand, scored his only Test try in a 22-15 home victory over Scotland in February 1980.
"Quite simply Irish rugby has lost one of its most genuine characters and legends of the game," said IRFU President Caleb Powell.
"Moss had ability on the field that no one could doubt from his record at club, provincial and international level.
"Lansdowne, Munster, Ireland and the British & Irish Lions all benefited from his presence and ensured that his reputation will live long in the memories of not only Irish rugby, but world rugby."