Don Ritchie, the man who saved more than 150 people from suicide spot The Gap in Sydney's east, has died aged 85.

Mr Ritchie, nicknamed the "Angel of the Gap", lived opposite the ocean cliff known as The Gap on South Head for more than five decades.

A former life insurance salesman, he said in the early years he physically restrained people from jumping while his wife called police.

In the later years he said he tried a more simple approach.

"[I'd say] 'What are you doing there? Why don't you come to our place across the road and have a cup of tea?'," he said.

Authorities estimate Mr Ritchie saved more than 160 people, but he said he believed other people would have done the same.

"You can't just sit there and watch them, I mean you've got to do something about it, anybody's like that. It gives them the chance of changing their lives," he said.

Mr Ritchie received an Order of Australia and last year was named Australian Local Hero of the Year.

NSW Minister for Mental Health Kevin Humphries says he had the privilege of meeting Mr Ritchie and was struck by his generosity of spirit, dedication and compassion.

Malcolm Turnbull, the federal Member for Wentworth where The Gap is located, called Mr Ritchie one of the greatest Australians.

"Don Ritchie, whose courage and compassion saved so many lives at the Gap, died yesterday. A true hero, one of our greatest Australians. RIP," he said on Twitter.