THE "Angel of The Gap", Sydney's Don Ritchie, has died aged 85.

Mr Ritchie spent 50 years coaxing desperate people back from The Gap, the notorious cliff at Watsons Bay where hundreds have died or thought about taking their lives.

He helped save 500 despairing souls - usually with little more than compassion, a warm smile and a hot cuppa.

"Those who knew him knew he was a very strong person and a very capable person," Mr Ritchie's daughter Sue said today.

Federal MP Malcolm Turnbull, whose electorate includes The Gap, added: "A true hero, one of our greatest Australians. RIP."

Born in Vaucluse in 1926, Mr Ritchie died peacefully at home on Old South Head Road, Watsons Bay yesterday.

The former navy seaman turned life insurance salesman was never one to shout about his exploits.

He helped because he could.

Ms Ritchie said: "It was just something that he saw and that he had to do something about."

New South Wales Mental Health Minister Kevin Humphries recalled when Mr Ritchie was named a Local Hero in the 2011 Australian of the Year Awards.

"Upon accepting the award Mr Ritchie urged people to never be afraid to speak to those most in need," he said.

"Always remember the power of the simple smile, a helping hand, a listening ear and a kind word."

A funeral will be held in Sydney on Friday.

Mr Ritchie's family asked for donations to be made to the Black Dog Institute or to Lifeline.

If you or someone you know may be at risk of suicide contact Lifeline 13 11 14, beyondblue 1300 22 46 36, or Salvo Care Line 1300 36 36 22.