WASHINGTON - Democrats in the U.S. Senate geared up for a fierce battle over a new healthcare reform plan on Thursday as Republicans condemned the bill's price tag and tax hikes before the first crucial test vote on Saturday.

Senate Democratic leader Harry Reid's 2,074-page blueprint for overhauling the $2.5 trillion healthcare system sparked what promises to be a long and bitter debate over President Barack Obama's top domestic priority.

The Senate will vote on Saturday night on whether to move to debate on the legislation -- the first key procedural hurdle for the Senate plan and one that requires 60 votes from the 100-member body.

The finish line is in sight, Reid said. I'm confident we'll cross it soon.

Whether Democrats succeed depends on Reid's ability to keep his party's caucus intact. There is no room for error -- Democrats control exactly 60 votes, and Republicans so far are united in opposition.

Reid dodged questions about whether he had the votes to move forward, telling reporters, We'll find out.

If the Senate agrees to take up the bill, the debate would begin on November 30, after next week's U.S. Thanksgiving holiday. It would last at least three weeks, making it unlikely Obama can sign a final bill by the end of the year.

Any differences between a Senate bill and the House of Representatives version passed on November 7 would have to be reconciled before a final bill can be voted on again in both houses and sent to Obama to sign.

The nonpartisan Congressional Budget Office estimated Reid's bill would cost $849 billion over 10 years -- below Obama's $900 billion target -- reduce the budget deficit by $130 billion in the same period and extend insurance coverage to 31 million more people.

The rosy report card from budget analysts could ease doubts about the bill among wavering moderate Democrats, but Republicans were not impressed.

We've been warning the American people of the Democrats' plans to raise premiums, raise taxes, and slash Medicare in order to fund more government, Republican leader Mitch McConnell said.

CHEAPER THAN HOUSE

The Senate bill is less expensive than a more than $1 trillion healthcare measure passed in the House, which would have covered at least 5 million more uninsured.

Like the House bill, the Senate measure would require all Americans to buy insurance and would set up exchanges where they could choose among various options. It also would offer subsidies to help low-income workers pay for the coverage.

The Senate bill includes a government-run insurance option that lets states choose whether to participate, and would halt industry practices like denying coverage to individuals with pre-existing conditions.

Some business trade groups were unhappy about the proposal, including America's Health Insurance Plans, which represents the insurance industry, and the National Federation of Independent Business, which represents small businesses.
The new healthcare taxes and fees will raise the cost of coverage for individuals, families, and employers, said Karen Ignagni, president of America's Health Insurance Plans.

Healthcare investors were mostly unconcerned about the Senate bill as most provisions were expected, but a surprise proposal for a 5 percent tax on cosmetic treatments hurt companies such as Allergan Inc and Medicis Pharmaceutical Corp.

Republicans criticized tax increases in the bill to help pay for the expanded insurance coverage, including the new tax on elective cosmetic surgery they dubbed a Botox tax.

The bill would also raise the Medicare payroll tax on high-income workers, which is used to finance the government health program for the elderly, and impose a tax on high-cost Cadillac insurance plans.

McConnell noted some of the bill's deficit reduction was possible because many of its provisions would not kick in until 2014, a year later than in the House bill.

That's a little bit like being asked to pay your mortgage four years before you're allowed to move into your house, he said.

Three Democratic senators -- Ben Nelson, Blanche Lincoln and Mary Landrieu -- are uncommitted on Saturday's vote, although Nelson and Landrieu said they were encouraged by Reid's approach. Nelson played down the vote's significance.

It's a simple vote -- to go forward with debate or not to go forward with debate, he said. Even if you don't like the legislation, it's arguable you should go ahead. If you don't get it on the floor, you don't have any opportunity to amend it.

Senator Olympia Snowe, the only Senate Republican to back a healthcare bill in committee, said she would vote with her fellow Republicans to block further debate on Reid's bill.

It does weigh in with more taxes and more spending, she told reporters.

(Editing by Arshad Mohammed and Peter Cooney)