The White House and allies in Congress punched back hard Monday after the insurance lobby fired off a surprise offensive at a pivotal moment of President Barack Obama's health reform drive.

Democrats dismissed an industry report which warned the reform bid would send costs soaring as a "hatchet job," a day before the Senate Finance committee was expected to vote largely on party lines to back a reform bill.

A study by auditors PricewaterhouseCoopers (PWC) for the insurance lobby warned that the bill before the committee would hike projected cost increases per family by 1,700 dollars in four years, and by 4,000 dollars in the next decade.

The America's Health Insurance Plans (AHIP) lobby group, which commissioned the report, argued that new taxes on health insurance plans, medical device manufacturers and pharmaceutical giants would pass on extra costs to consumers.

The report marked a change of tactics: the industry, blamed for killing a health reform effort by then president Bill Clinton in the 1990s, had previously worked to influence this bill in talks with the Obama White House and in Congress.

The White House, which has waged a months-long campaign against conservative critics of its attempt to cut health care costs and to make treatment affordable to all Americans, quickly dismissed the credibility of the report.

"This is a self-serving analysis from the insurance industry, one of the major opponents of health insurance reform," said Reid Cherlin, a White House spokesman.