Mr Mundine described Thursday's announcement by Attorney-General George Brandis as a joke and a waste of money, claiming it was thought up by a "dickhead".
When asked by Neil Mitchell on 3AW radio, if Senator Brandis was a "dickhead", Mr Turnbull did not respond but said while about three per cent of Australians identified as Aboriginal or Torres Strait Islanders they represent 25 per cent of the prison population.
Indigenous Australians made up 14% of the national prison population 25 years ago - by 2015 it was up to 27%
That was an enormous, complex problem, he said foreshadowing taking recommendations from a report on the issue to a COAG meeting with state and territory leaders later in the year.
"I don't want to buy into an argument with Warren but there are no silver bullets here," Mr Turnbull said, noting the Australian Law Reform Commission review had been welcomed by just about everyone except for Mr Mundine.
"On this occasion he may be wrong and he should reflect on that," he said.
Ken Wyatt, the House of Representatives' first Indigenous member, told ABC radio the review was important because it would look at legislation and practices that have "crept" in since the royal commission into Aboriginal deaths in custody 25 years ago and have resulted in an increase in incarceration rates.