Former Te Tai Hauāuru MP and government minister Dame Tariana Turia said this was an issue of institutional racism and government inaction.
"We can look at everything that's wrong within families or we can address the system. When you have a racially biased system, we shouldn't be surprised about what the outcome is," she told the Chronicle.
"The issue of institutional racism has been raised for a number of years, and generally not by Maori but those people who understand statistics and who study these issues in depth.
"No matter what has been said to the state about its agencies and how they operate, they continue to operate in the same way because they always look at the people as the problem, rather than looking at the system as contributing to the problem."
Dame Tariana added: "They've all behaved the same - buried their heads in the sand and blamed the people.
"It's much easier to do that, but it doesn't take into consideration the impact of policy on those people.
"The state has to take responsibility - it doesn't seem to be working, so why don't we try something else?"
Annual imprisonment numbers have halved in the Whanganui-Taranaki court region in the past seven years, falling from the peak of 793 in 2009 to 375 last year.
Justice Minister Amy Adams said tackling the issue of over-representation of Māori in the justice system was a priority.
"While there has been a significant reduction in total crime over the past five years for both Māori and non-Māori, these reductions have not been as large for Māori when compared to non-Māori, and this means that Māori over-representation has not improved," she said.
Nationwide last year, Māori convicted of crimes were imprisoned at a higher rate than any year since records began in 1980. More than 17 per cent received jail time, compared to 10.3 per cent of pakeha.
Fifty-six per cent of all people imprisoned in 2016 were Māori - also the highest figure ever recorded.
Ms Adams said the Government had implemented "a range of programmes and initiatives" which aimed to address high Maori represntation in the justice system.
These include the Youth Crime Action Plan, restorative justice services with Māori values, Māori and Pacifica Youth Courts and iwi panels for low level offending as a form of alternative resolution.