Obama delays trip for health care bill

MPs may get the chance to have lunch with US President Barack Obama during his visit to Australia.

US Democratic leaders are unveiling what is expected to be their final health care bill, setting the stage for a Sunday vote on a plan that would affect most Americans and has become the defining issue in Barack Obama's presidency.

Leaving nothing to chance, the White House said Obama had put off his planned trip to Australia and Indonesia for a second time, delaying it until June. Obama was to have left on Sunday.

House Speaker Nancy Pelosi said on Thursday: "He wants to be here for the history."

The plan would cost $US940 billion ($A1.02 trillion) over 10 years and extend coverage to 32 million Americans who are uninsured, while reducing the federal deficit by $US138 billion ($A149.5 billion) over 10 years, the impartial Congressional Budget Office said, and continue to drive down red ink thereafter.

Democratic leaders said the deficit would be cut $US1.2 trillion ($A1.3 trillion) in the second decade.

The plan would restructure one-sixth of the US economy in the biggest expansion of the social safety net since 1965.

Though the vote is expected on Sunday, passage is still not assured. With Republicans unanimous in opposition, Obama needs to win over moderate House Democrats, some of whom are wary about the plan's costs and abortion provisions.

Still, Obama appears on the verge of a victory on the signature issue of his presidency. Democrats in January lost a Senate seat in a special election, denying them the 60-vote supermajority needed to overcome Republican blocking tactics. But Democrats are using a complicated legislative strategy to get the bill through both the House and Senate.

Obama called it the biggest deficit reduction since the 1990, when president Bill Clinton put the federal budget on a path to surplus.

The Democrats' drive took on a growing sense of inevitability this week, picking up endorsements on Wednesday from a longtime liberal holdout and from a retired Catholic bishop and nuns who broke with church leaders over the bill's abortion provisions.

Leaders appeared increasingly confident of getting the 216 votes they need.

The health care issue is likely to shape the November congressional election, when Republicans try to capture both chambers.

Once the legislation is fully phased in, most Americans would have to carry coverage - and insurers would be forbidden from turning down people with health problems or charging them more.

The big expansion of coverage would not come until 2014, when new health insurance marketplaces open for business.

In the meantime, the legislation calls for new consumer benefits. Insurers could not deny coverage to children with a pre-existing health problem, or place lifetime dollar caps on the amount of coverage. A new high risk health insurance pool would provide coverage to uninsured people who can't get private coverage because of health problems.

Democrats are following a two-track legislative strategy. First, the House, despite the reservations of many Democrats, will have to endorse a bill approved by the Senate last year. Then both chambers will quickly pass a package of fixes agreed to in negotiations with the White House. The Senate would use a procedure that requires only a simple majority, avoiding Republican delaying tactics.

With Democrats promising 72 hours for lawmakers and the public to review the legislation once released, that would push a House vote on the bill until Sunday at the earliest.