Washington, July 28: The US Senate rejected a scaled-back Obamacare repeal bill on Friday in a shocking vote that marked a major defeat for Republican leaders and their seven-year effort to repeal the healthcare law, the media reported.

The Senate voted 49-51 against the "skinny" bill that would have repealed Obamacare's individual and employer mandates and defunded Planned Parenthood, The Hill magazine reported.

Republican Arizona Senator John McCain cast the decisive vote to defeat the proposal called the Health Care Freedom Act, joining two other Republicans, Susan Collins of Maine and Lisa Murkowski of Alaska, in opposing it.

"I do my job as a senator," Politico news quoted McCain as saying after he left the Senate chamber.

McCain said he voted against the Obamacare repeal bill "because I thought it was the right vote" and also because it did not offer an "adequate replacement".

In a speech from the Senate floor, Republican Senate Majority Leader Mitch McConnell said "it is time to move on".

"What we tried to accomplish for the American people was the right thing for the country."

"I think the American people are going to regret that we couldn't find another way forward," McConnell said.

President Donald Trump blasted lawmakers for failing to pass the "skinny" bill.

"Three Republicans and 48 Democrats let the American people down. As I said from the beginning, let Obamacare implode, then deal. Watch!" Trump tweeted.

The US President ran on the promise of repealing and replacing his predecessor Barack Obama's 2010-promulgated health reform called the Affordable Care Act and has been pressuring Republicans for months to put forward and pass a repeal bill.

Ahead of the vote, many Republican senators admitted that the measure was not good policy, but, in a highly unusual situation, said they were voting for it simply to advance the process and set up a negotiation with the House on a new bill, in what is known as a conference committee, the report said.

The Congressional Budget Office found that the bill would result in 16 million more uninsured people and roughly 20 per cent higher premiums, largely from repealing the mandate to have insurance.

Republicans pointed out many of those people would choose not to buy insurance, without the mandate.

US Senate rejects Obamacare repeal bill