Both bills would raise tobacco taxes. The federal excise tax on cigarettes would rise to $1 a pack under the Senate bill and to 84 cents a pack under the House measure, from 39 cents a pack.

The House bill would sharply reduce federal subsidies paid to insurance companies offering private health plans to Medicare beneficiaries. Many Democrats say these plans, which serve nearly one-fifth of the 43 million Medicare beneficiaries, are overpaid. The Senate bill does not deal with Medicare.

Michael O. Leavitt, the secretary of health and human services, said Congress was jeopardizing health care for millions of needy children by passing bills that “the president will have no choice but to veto.”

Senator Charles E. Grassley of Iowa, a Republican who helped write the Senate bill, said he intended to try to persuade Mr. Bush to sign the legislation that emerges from Congress. But Mr. Grassley said that he would fight the proposed cuts in Medicare payments to private plans.

“It’s a question of equity for rural America,” Mr. Grassley said. “Before 2003, rural Medicare beneficiaries rarely had private Medicare plans to choose from. They did not have the same choices people have in urban America. These plans can be a good choice for people with a chronic illness, for lower-income people and for those who want extra benefits.”

Insurers say the private plans would disappear from many parts of the country if Medicare payments were cut as proposed by House Democrats.

But AARP, the lobby for older Americans, has endorsed the House bill. It says the “excess payments” to private plans cause higher premiums for all beneficiaries, including those in traditional Medicare.