Haslam said in a speech to the Nashville Rotary Club that he was unsettled by the lack of guidelines from the federal government about the insurance marketplaces that are required under President Barack Obama's health care overhaul.
"This is a massive federal program to be implemented across millions of individuals, and the amount of information and data that we have about it -- or the lack of that -- is scary, quite frankly," Haslam said.
"I'm more and more convinced they're making this up as they go," he said.
Exchanges are new online markets where consumers will be able to buy individual private policies and apply for government subsidies to help pay their premiums. About 30 million people around the country who are expected to gain coverage under the law will get policies in the new exchanges, and the other half will be covered under Medicaid. About 982,000 people are uninsured in Tennessee.
Friday is the deadline for states to decide whether they will create a state-run exchange, let the federal government administer it or create a joint marketplace. Haslam said there was too much uncertainty in having the state run the program.
"As the CEO of the state of Tennessee I'm being asked to make a significant business decision based on information that's only now dribbling out of Washington and that we appear to have little influence over," Haslam said.
The governor denied that political calculations influenced the decision, though he acknowledged that getting a state-run exchange approved by the Legislature would have been a difficult prospect. His deliberations over the proposal had led to tea party supporters protesting outside the Capitol last week, deriding it as "Haslamcare."
"If it was a political decision we would have made it months ago -- the politics of this were clear from the beginning," he said. "It was our responsibility to find out what really is the best answer for Tennessee."
Reaction to the decision nevertheless played out along partisan lines Monday.
"I'm disappointed to see the governor pandering to the far right of his party rather than doing what is best for the people of Tennessee," House Minority Leader Craig Fitzhugh, D-Ripley, said in a statement.
Meanwhile, a series of Republican lawmakers lauded the governor's choice.
"It is the right decision for Tennesseans and one of the few remaining ways to fight the government takeover of health care," said state Sen. Jim Tracy, R-Shelbyville. He also urged the governor to reject Medicaid expansion.
House Speaker Beth Harwell, R-Nashville, also agreed with Haslam's approach to the exchange.
"The decisions regarding health care are best left to each Tennessean and their doctor-- not a massive bureaucracy that is sure to send this country further into debt," she said.
Haslam said a decision on Medicaid expansion may not come until after the Legislature adjourns this spring.
"The expansion does not have that timeline, but to be fair to our health care providers, we're going to try to do that as quick as we can," Haslam said.