Rugby league coach of the century Jack Gibson has died after a lengthy illness.

His family today said the five-time premiership winning coach had passed away at 6.32pm AEST in Sydney after suffering from Alzheimer's disease and dementia for the past two years.

Gibson was last month named as the coach of rugby league's Team of the Century, with his passing marked tonight with a minute's silence before kickoff at the Centenary Test between Australia and New Zealand at the SCG.

"Jack passed away comfortably today, at 6.32pm at the Garawarra Centre, Waterfall, surrounded by his family,'' a statement said.

"We greatly appreciate the wonderful care he had received at Garrawarra, and also the caring and kind support afforded to us, the family.

"We are dealing as well as we can and would ask that Jack's many friends in their sadness that he is no longer with us, do not feel too sorry.

"Jack would not want that; it was his own strong belief and appreciation that he had had a very fortunate life, and we know he would have wanted that to be the spirit of this time.''

Gibson won a total of five premierships with Eastern Suburbs in 1974-75 and Parramatta between 1981-83 and earned the nicknamed "Supercoach" after revolutionising the role.

A former Easts, Newtown and Western Suburbs front-rower who played 162 first grade games, Gibson began coaching at the Roosters in 1967, taking the Bondi side that hadn't won a game the previous year to the semi-finals.

His Roosters teams in 1974-75 and the Eels teams of 1981-83 are regarded as some of the most brilliant club teams ever assembled.

He also coached the NSW State of Origin team in 1989-90.
Apart from his premiership-winning ability, Gibson was also famous for his

one-liners as a commentator, his charity work and the coaching techniques he sourced from professional American football clubs.

Eels great Peter Sterling, who played halfback for Gibson in Parramatta's hat-trick of premierships, said tonight he had been "absolutely shattered'' by news of his former coach's death.

"I played under Jack Gibson for a number of years, won three premierships and I'm absolutely shattered,'' said the Network Nine commentator.

"I guess we knew this night was coming ... but it's very hard to digest.

"Jack, he loved his players, he cared about his players. And I think the great thing about being coached by Jack Gibson ... is he was more concerned about you off the field than he ever was on (the field).

"He made wonderful footballers, but he also made wonderful people and I thank Jack Gibson eternally for being a part of my life and I know I speak on behalf of every rugby league player and every rugby league supporter who was lucky enough to see Jack in action.''

AAP