WASHINGTON, US - US Senate Democrats geared up for a lengthy battle over a new healthcare reform plan on Thursday as Republicans condemned the bill's cost and taxes ahead of the first key vote this weekend.

Senate Democratic leader Harry Reid's 2,074-page blueprint for overhauling the US$2.5 trillion($3.4 trillion) healthcare system quickly launched what promises to be a long and bitter debate over President Barack Obama's top domestic priority.

Reid said the Senate will vote on Saturday 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."

But 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 so far Republicans are united in opposition.

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

If the Senate agrees to take up the bill, the debate is expected to begin on Nov. 30, after the US Thanksgiving holiday next week. It would last for at least three weeks.

Senior Democratic senators have said it is unlikely Obama will have a completed bill on his desk by the end of the year.

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

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 US$1 trillion healthcare measure passed on Nov. 7 in the House of Representatives. That bill would have covered at least 5 million more uninsured.

Like the House bill, the Senate measure mandates that most Americans buy insurance and sets up exchanges where they could choose among various options. It also would offer subsidies to help the lowest-income Americans 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 with the bill, 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 appeared mostly unconcerned about the Senate's version of the bill as most provisions were expected, but a surprise proposal for a 5 per cent 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 deficit reduction in the bill 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.

The rosy budget report card on the Senate bill, unveiled on Wednesday night, cheered Senate reform advocates and could help convince party moderates who have not committed to back Reid on Saturday's vote to begin debate.

Three Democratic senators - Ben Nelson, Blanche Lincoln and Mary Landrieu - are still uncommitted, although Nelson and Landrieu said after the bill was released they were encouraged by Reid's approach.

The vote on whether to move to the debate might occur on Saturday night to accommodate Senator Joe Lieberman, an Orthodox Jew who refrains from political activity on the Jewish Sabbath, a Democratic aide said.

If the Senate passes a bill, any differences with the House version would have to be reconciled before a final bill can be voted on again in both houses and sent to Obama to sign.