Eleven of the nation’s largest business groups are beginning a multimillion-dollar TV ad campaign that says the health overhaul legislation in the House would raise taxes and worsen the economy without curbing medical expenses.

The commercial is the latest example of stepped-up opposition by large segments of the business community as the House and Senate prepare to vote on Democratic bills revamping the nation’s health care system.

Calling themselves Employers for a Healthy Economy, the coalition of sponsoring groups ranges from the National Federation of Independent Business, which represents small businesses, to organizations representing large corporations like the U.S. Chamber of Commerce.

The House plans to vote on the Democratic-written legislation this week. Senate Democratic leaders have not written a final version of their legislation. Last week, the U.S. Chamber of Commerce expressed “severe disappointment” with the new health care bill introduced in the House of Representatives on Thursday, citing concerns that the “wild spending” in the legislation would burden a fragile economy and tax small businesses.

The inclusion of a government-run insurance option would result in costs shifting to private payers and wouldn’t address affordability, Bruce Josten, executive vice president of government affairs for the U.S. Chamber of Commerce, said in a statement.

“A government-run plan cannot operate on a level playing field and compete fairly,” Josten said. “Market-driven health reforms are the best approach to reducing costs, promoting efficiency, wellness, and quality of care.

“Whether reimbursement rates are tied to Medicare or are ‘negotiated’ by the Secretary of HHS, the fundamental reality remains that the public plan would have devastating effects on the rest of the market and the government would still be setting prices that would be below actual market rates.”

Elsewhere, mandates on larger employers would reduce employer flexibility and result in job loss and lower wages, he said. Also, the chamber opposes the proposed additional taxes imposed on individuals for not purchasing coverage or for employers not offering coverage, he said.

“Employer mandates . . . are not the answers to our nation’s health care challenges. . . . Preserving employer flexibility is critical for ensuring quality care,” Josten said.