Washington (Agencies): President Barack Obama's Democratic partners in the US Senate have defeated a Republican push to abolish his landmark health care overhaul, likely leaving its fate in the hands of the courts.

Lawmakers voted 47-51 along party lines to allow the repeal drive to move ahead— well short of the 60 votes necessary—as the Obama administration geared up to fight judges' rulings declaring his signature overhaul unconstitutional.

Observers said challenges to the sweeping overhaul, one of the signal wins of Obama's first two years in office, will likely wind up before the US Supreme Court, the final arbiter of the US Constitution.

Senators also voted 81-17 to strip out a small tax paperwork requirement, a step Democrats portrayed as a symbol of their eagerness to mend, but not end, the health care law.

"Democrats have said we are willing to compromise on common-sense fixes," said Senate Majority Leader Harry Reid adding, "But Democrats will not compromise if it means undoing the progress we've made toward fixing a broken system."

Republicans, all 47 of whom voted to scrap the step, knew they could not prevail but aimed to force Democrats thought to be vulnerable in 2012 elections to take what could be a politically painful vote.

The law, which Obama signed in March after a year-long battle, aims to spread coverage to 31 million of the 36 million Americans who currently lack insurance.

Although the United States is the world's richest nation, it is the only industrialised democracy that does not provide health care coverage to all its citizens.

The Senate vote came after the Republican-held House of Representatives voted 245-189 to repeal the health care legislation and then moved to start crafting their party's version of the overhaul.