The United States' landmark health care legislation passed a crucial procedural test in a Senate vote in the wee hours of Monday ahead of a final vote later in the week.

The Senate voted 60-40 along party lines to end debate on the bill, which would extend coverage to more than 30 million Americans who now lack it.

"What's really killing more and more Americans every day is complications from our health care system," Democratic Senate Majority Leader Harry Reid said before the ballot.

Under congressional rules, the vote is the first of three separate votes to finally pass the 871-billion-U.S.-dollar overhaul of the U.S. health care system.

A final vote is expected on Wednesday or Thursday.

The health insurance reform is the top domestic priority of President Barack Obama. The bill also eyes banning insurance company practices such as denial of benefits on the basis of pre-existing medical conditions.

The United States is the only wealthy industrialized nation that does not have universal coverage of health insurance, which is provided primarily by employers in the United States.

Due to rising unemployment rate in the recent recession, the number of uninsured have been growing.

In the latest of a series of deals struck by Democrats to hold together their party to support the legislation, the last holdout Democrat Senator Ben Nelson (D-Nebraska) agreed on last Saturday to support the bill in return for compromise language on federal funding for abortion and more money for his state.

Afterwards, Majority Leader Harry Reid of Nevada claimed that the bill has gained support from all 60 members of the Democratic caucus in the Senate.