U.S. President Donald Trump says he hopes Republican senators will vote for new legislation that aims to repeal and replace the health care law enacted by his predecessor.

Trump says on Twitter that the so-called Graham-Cassidy bill is "GREAT!" and "Ends Ocare!" a reference to "Obamacare," the colloquial name for the set of health laws in place in the United States.

Republican Senators Lindsey Graham of South Carolina and Bill Cassidy of Louisiana are the sponsors.

The 140-page bill would replace much of Obama's statute with block grants to states and give them wide leeway on spending the money. It would let states ease coverage requirements under that 2010 law, end Obama's mandates that most Americans buy insurance and that companies offer coverage to workers, and cut and reshape Medicaid.

The Congressional Budget Office (CBO) said Tuesday it would take weeks to assess the implications of the bill, despite the possibility of a vote as a early as next week. Previous Republican repeal efforts reviewed by the CBO were shown to result in millions of people losing their insurance coverage.

Senate Republicans defeated an effort earlier this year to repeal Obama's law.

Trump also criticizes Kentucky Republican Sen. Rand Paul for opposing the bill. Trump says Paul is "such a negative force when it comes to fixing health care.

Democrats backed by doctors, hospitals, and patients' groups mustered an all-out effort to finally smother the GOP drive this week, warning of millions losing coverage and others facing skimpier policies. Senate Minority Leader Chuck Schumer went further, saying the partisan measure threatened the spirit of co-operation between Trump and Democratic leaders embodied in a recent budget deal and progress on immigration.

"After two weeks of thinking bipartisanship, that flickering candle, might gain some new light, this is the last thing we need," Schumer, from New York, said on the Senate floor earlier this week.