The system for helping them was so overloaded that social workers could only spend a few minutes with them every week.
"The system is geared to fail, because the one thing that suicidal people need is your time."
Mr King is a well known comedian.
But for the last four years he has been presenting radio and television shows about mental illness, called The Nutters Club, and he fronts The Key to Life charitable trust.
He speaks to young people in schools weekly and mentors about 30 South Auckland young people who are depressed and suicidal.
"I spend five or six hours a day with them sometimes, for three, four and five days in a row. These are kids that have been abused so badly they have no self esteem whatsoever."
Because they had been let down so often, their first impulse when anyone tried to get close to them was to push that person away.
"You have to push back, with love, and keep turning up. You've got to remember that if you don't persist with these people then the outcome doesn't bear thinking about."
It was hard to get professional help, and he ended up paying psychologists to talk to them.
"I have got a network of psychologists who give their time half price."
Going to young people thinking he had the answers and they would rejoice in his wisdom had proved to be a mistake.
"They helped me understand that the real answer lies with our rangatahi [youth].
"We should give them time to find their own answer.
"What we need to do is listen to our children and help them to achieve their goals and aspirations."
Talking about suicide was important, and he said a new public relations strategy would help.
Instead of the subject being all dark and dire, he suggested a television ad campaign fronted by a 12 to 14-year-old girl who would "make people smile".
"This young girl will educate us on how to talk to suicidal people."