MINNEAPOLIS — Gov. Mark Dayton lashed out at critics of Minnesota’s health insurance exchange on Tuesday, accusing them of waging a propaganda campaign to destroy it.

The Democratic governor spoke to reporters a day after GOP members of the Legislature’s MNsure oversight committee said they wanted to use a hearing set for Wednesday to raise tough questions about the troubled launch of MNsure last October and the decision to proceed despite evidence that the website still had serious problems.

Dayton called their plans for raising those issues a “farce.” Rather than focusing on problems that happened six months ago, he said, the important thing to know was that over 175,000 Minnesotans used MNsure to get health coverage by March 31, including many who didn’t have it before.

“The fact that they can pretend this is part of an oversight process is just ludicrous,” he said. “They just want to trash MNsure, they want to trash the Affordable Care Act, they want MNsure to fail.”

GOP Reps. Tara Mack, of Apple Valley, and Joe Hoppe, of Chaska, responded with a statement saying the oversight committee “isn’t a ‘farce,’ it’s the law. With recent news reports stating Governor Dayton and MNsure leaders chose to expose Minnesotans to a program that wasn’t ready for consumers, it’s clear we need more oversight of ObamaCare not less.”

Dayton said he wouldn’t send any of his advisers to speak at the hearing. While the committee had added his human services commissioner, Lucinda Jesson, to the agenda, and her office initially confirmed that she planned to appear, she soon backed out.

“The MNsure board will be well represented by (chairman) Brian Beutner and (interim CEO) Scott Leitz at tomorrow’s MNsure Legislative Oversight Committee hearing, and Commissioner Jesson will not attend the hearing. She has no further comment on the matter,” the department said in a statement.

MNsure leaders chose to launch the website even though they knew it was loaded with bugs, and that MNsure’s executive director at the time, April Todd-Malmlov, warned the governor at a meeting 12 days before the system went live that nobody was certain if the site would work.

Dayton insisted that the Sept. 19 meeting was the first time he learned that problems with the website were serious enough to call into question whether MNsure could proceed with the launch on the same day open enrollment began across the country under the Obama administration’s health care overhaul. But he said his office kept in close contact with MNsure officials throughout the process and he thought enough problems would be resolved in time.

Even in hindsight, Dayton said, he still believes the decision not to delay was correct. He said he thought the system was operating “very well” at first and that its glitches were due mostly to problems with the federal system. He said he “didn’t have any inkling of persisting problems until the middle of November” when he said new problems kept cropping up every time old issues got resolved. He also said he never tried to mislead Minnesotans on MNsure’s condition.

And the governor said critics of MNsure and the Affordable Care Act haven’t offered an alternative except going back to the way things used to be.

“To evaluate the success or failure six months into the undertaking is just really shortsighted and unrealistic,” he said. “It’s going to take a couple years to get things ironed out, to get it working the way it should. Then we can evaluate the costs and benefits.”