Senate Appropriations Committee chairman Jack Gordon says he had heard estimates that as many as 75,000 ineligible people are receiving Medicaid payments.
Francis Rullan, a Medicaid spokesman, however, says abuse is not a widespread problem in the program that serves 786,000 Mississippians.
He said, "I would be amazed if it even approaches $30 million."
On Friday, The Associated Press learned that Medicaid also could have overpaid health care providers millions of dollars over the past three years. Rullan disputes those claims as well.
Attorney Gen. Jim Hood provided The A.P. with a report that said Medicaid costs, for various reasons, have increased 48 percent in four years.
The report said eliminating Medicaid abuse could save the state $18 million to $36 million per year.
Lawmakers are planning to meet Monday to discuss the ailing program for the needy and elderly.