Forecasts of dramatic jumps in U.S. medical costs are pushing lawmakers to reach a deal on a major healthcare revamp that seeks to extend coverage to all Americans, a leading U.S. senator said on Thursday.

Senate Finance Committee Chairman Max Baucus, a Democrat with a lead role in crafting the proposed overhaul, said he saw a 75 percent to 80 percent likelihood that legislation will pass the U.S. Senate with broad support from Democrats and Republicans.

I think at the end of the day, every Democrat and a good number of Republicans will agree, Baucus said.

Congress has struggled for decades to expand medical coverage to uninsured Americans and President Barack Obama has made healthcare reform an immediate priority.

Baucus said lawmakers were now motivated by sobering projections of rising health costs and millions more uninsured Americans, now estimated at about 46 million, if they fail.

Baucus spoke as the Robert Wood Johnson Foundation, an independent healthcare research group, released a study that said the number of uninsured Americans could soar to more than 65 million in 10 years as healthcare costs more than double.

In the worst case scenario, the number of uninsured Americans would increase to 57.7 million in 2014 and to 65.7 million in 2019, the report concluded, adding that without major changes the number would grow to at least 57 million in the next 10 years.

Mostly middle-income and even some high-income families would join the ranks of the uninsured, the study concluded. Rising health costs also will hurt employers who provide health insurance to their workers, it said.

Federal and state governments would take big budget hits as they struggle to cover low income children and pay for rising costs in the Medicare and Medicaid health programs for the elderly and poor, the report said.

OBSTACLES AND DEADLINES

A sticking point is what role the government will play in covering the uninsured. Democrats want a new public plan to compete with private insurers but Republicans and private insurers say that could drive companies out of business.

Lawmakers must cut costs and raise revenues to pay for a policy some experts say could cost as much as $1.5 trillion. Some proposed measures are controversial, including raising federal alcohol taxes and a proposed tax on sugary drinks. Lawmakers also are looking at taxing some employer-provided insurance benefits, a move opposed by unions.

Obama wants to sign an overhaul of the $2.5 trillion U.S. healthcare industry into law by the end of the year and Baucus told a briefing sponsored by the Kaiser Family Foundation that his committee was on track to meet that goal. The committee expects to act on a bill and send it to the full Senate by mid-June, he said.

Democratic leaders in the U.S. House of Representatives said they expect that chamber to pass its version of legislation by August. That would give the two chambers time to work out their differences and meet Obama's deadline.

Baucus has been meeting with lawmakers, industry and consumer groups to try to reach broad consensus. He said the bill would aim to reduce costs and cover as many people as possible without adding to huge U.S. budget deficits.

We are not going to get 100 percent coverage but we are going to try to get as close as we can and we are working hard to accomplish that, Baucus said.

Baucus said some people always will fall through the cracks and that it would be politically explosive to include undocumented workers in the coverage plan. But he said he felt the country would get the change it needed.

Nearly everybody is going to get health insurance, Baucus said.

(Editing by Bill Trott)