Lieberman, appearing on CBS's "Face the Nation," said he disagreed with Senate Democrats who support the public option measure, which they say is needed to provide competition for private insurers who enjoy monopolies in many markets.
"I feel so strongly about the creation of another government health insurance entitlement," he told CBS. "The government going into the health insurance business -- I think it's such a mistake that I would use the power I have as a single senator to stop a final vote."
The former Democrat said doing nothing would be better than a public option.
"We ought to follow the doctors' oath and say, 'First, let's do no harm,'" he said, adding that he believes a public option would hurt the country's economic recovery, predicting that if adopted it would necessitate tax hikes.
"It will probably raise premiums or it will put us further into debt," he said, asserting that the idea has been advanced by "people who really want to have a government-controlled health insurance system. That's their right. I think they're wrong."