Davis spoke of a former inmate called Sam, who he met at a marae in Whangarei.
He said Sam told him he had "never been hit or abused" until he was taken from his family of 16 children by a government which considered the burden was took much for his parents to shoulder.
He was placed with a boys' home in Levin - the former Hokio Boys' Home features in the stories of many caught in a life of crime - when he stayed four years.
"He had never known abuse or violence in his life until he walked through their doors."
When he returned to Auckland, he felt alien in the city which had once been home and joined a gang inside a fortnight.
That bond with the gang lasted for 48 years, his life on a path that began with the state removing him from his home, Davis said.
"Sam is now 60. The gang patches on his face still vivid. His life has been spent in and out of prison.
"Why didn't we do something? As a Government, as Māori: Why didn't we help?"
"There had to be dozens of points in Sam's life when someone could have stepped in."
Davis said the one time the state did step in, it was to take him from his family which "sent him down the path that ultimately turned him into a gang member" along with his whanau.
"It's our fault he spent nearly half a century in a gang."
Davis said there were "5000 Sams" in prison - the number of Maori currently incarcerated.
"We need to do something together to create a different future for Māori and for their whanau.
"We need to break the cycle, connect them to their people, help them, and have hope for them. And if we accept that there is a need for change – then we must all be part of that."
Davis said the system needed change but the Government also needed to change its attitude and its systems.
"As a Government we need to make sure the system helps and does not hurt Māori further.
"We need to make sure those who have found their way into the system leave as better people - not broken people."
Davis said the greater proportion of Maori in the prison system meant it was for Maori to "lead the solution".
He said about half of those Maori in prison were from his iwi, Ngāpuhi. He had whanau in prison and childhood friends. "That's not to excuse the offences these people have committed – but something has to be done to reduce the scale of this problem and the sheer waste of human potential."
Davis said the problem was not new, and previous governments had failed to accept or overcome the challenge.
"We take pride in New Zealand as a country that leads the world in many ways.
"But there is an ugly reality in this country. We are a world leader when it comes to putting people in prison. We can't seem to get enough of it."
Davis' comments echo Prime Minister Jacinda Ardern's speech last night during which she said New Zealand's vision of itself did not match reality.
Justice minister Andrew Little went down the same path at the justice summit.
"We are surrounded by phenomenal beauty … but we have an ugly side to New Zealand too.
Little spoke of "grinding poverty", homelessness, mental health services which were under pressure and an education system which still allowed children to "slip through the cracks".
He also spoke of the high rate of Maori imprisonment and how government spent much on "locking people up" but paid less attention to the high rate of mental health and addiction issues of those in prison.
Police minister Stuart Nash also spoke of New Zealand's image of itself.
"We think we're growing up in a country of equality. We need to think again."
He said New Zealand had a choice - continuing to take a punitive approach to crime and punishment, which would lead to higher prisons, or a compassionate approach.
He said it was easy to be punitive, although compassion was cheaper and more effective.
"This is not about being soft on crime at all."
