"Don't do it for me, don't do it for the Democratic Party, do it for the American people. They're the ones looking for action right now."

Obama needs 216 votes in the House if the measure is to pass.

If successful the healthcare reform bill would extend coverage to 32 million more people, so that 95 per cent of Americans would have healthcare coverage.

'Kill the bill'

Critics of the measure have said they fear the move will make abortion easier.

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But Democratic leaders indicated that they had overcome disagreements within their ranks over abortion funding restrictions in the measure.

Meanwhile, crowds of protesters demonstrated against the measure outside the Capitol building as Obama spoke on Saturday, holding signs that read "Kill the bill" and "Get your hands out of my pocketbook and health care".

The legislation, which would prevent insurance companies refusing coverage to those with pre-existing medical conditions, has topped Obama's domestic priority list.

According to the latest Gallup poll, only 48 per cent of Americans approve of Obama's performance in office; his lowest numbers as president. Only 45 per cent support his healthcare plan.

With polls providing a mixed picture of their attitudes, the president has made clear he is willing to let voters decide in November whether healthcare should be approved or not.

With more than one-third of the senate and all seats in the House of Representatives up for grabs, his fellow Democrats want to move past healthcare to focus on job creation and the economy.

Obama acknowledged on Saturday that backing the bill would be a tough decision.

"I know there is a tough vote," he said.

"And I am actually confident, I've talked to some of you individually, that it will end up being the smart thing to do politically because I believe that good policy is good politics."

If the measure clears the House vote, the US Senate would take up the changes next week.