The department received only a 1 percent increase in its budget for fiscal year 2014.
More Oklahoma inmates have been moved to private prisons.
Former state Speaker of the House Kris Steele, who helped craft the 2012 Justice Reinvestment Initiative — aimed at helping cut the prison population — said the state needs to take more steps to address the problem.
“We're going in the opposite direction,” Steele said.
The initiative received less funding than requested, and many of the provisions have not been implemented, he said.
“There are smarter, more effective ways” to deal with many offenders than solely incarceration,” Steele said.
He cited other states, such as Texas, that have used similar justice initiatives to reduce their prison population during the past couple of years.
In Oklahoma, with prison facilities nearly maxed out, “the trends are unsustainable,” Steele said.