Flags at the Millennium Stadium are flying at half mast from today in honour of Davies who died following a long illness.
A minute’s silence will be held in tribute to Davies at all Wales international games across the weekend.
Everyone involved in the game in Wales offers their condolences to the family and friends of a true giant of the game who was known universally as ‘Merv The Swerve’.
Davies made his international debut against Scotland at Murrayfield in 1969 and led Wales to the 1976 Five Nations Grand Slam.
He won 38 caps for Wales and went on two British and Irish Lions tours to New Zealand in 1971 and South Africa in 1974.
Davies played for London Welsh from 1968 and later joined Swansea where he completed his playing career.
Welsh Rugby Union President, Dennis Gethin, said: “We have lost a great player, a wonderful ambassador for the game and a true gentlemen.
“I played against Mervyn many times and knew just how good he was but I also grew to appreciate him as a true friend. In later life he also became an accomplished after dinner speaker so his loss will be felt in many ways by so many people.”
Welsh Rugby Union Chairman, David Pickering, said: “Mervyn Davies was a man who epitomised the values of Welsh rugby and will be sadly missed by everyone who knew him and all who knew of him.
“He was a giant of the game both on and off the field for London Welsh, Swansea, Wales, the Barbarians and the British and Irish Lions. He bore his illness with courage and his memory will undoubtedly live on within our game for all time.”
WRU Group Chief Executive, Roger Lewis, added: “We have lost a true great of our game with the sad death of Mervyn Davies. He was a giant in all senses.
“His loss will be felt across the rugby world because of the huge impact he had as an icon of the game. He stood out in one of our great Welsh teams but remained a modest and gentle man off the field of play throughout his life. He was a modest, gentle but straight talking man.
“Mervyn also played a prominent role in Welsh international rugby’s former players association so his love of the game remained undiminished throughout his life.
“He truly earned his place in the Hall of Fame and it is right and fitting that this weekend his memory will be honoured by everyone involved in Welsh rugby.
“I want to send our condolences to all his family and friends because Mervyn Davies was a true great.”