Washington  - US President Barack Obama will seek to regain control of the health-care debate next week when he gives a major speech to Congress as lawmakers return from summer recess.

The fate of Obama's plans to overhaul the health insurance system is seen as an early test of his young administration that could largely shape his four-year term and his political clout in future legislative battles.

Democratic leaders in Congress have been urging Obama to get in front of the debate, after many of their centre-left lawmakers have endured harsh attacks from constituents during unruly townhall meetings in recent weeks.

"Clearly, over the August break we lost some momentum," Senator Charles Schumer, an Obama ally, told the Washington Post. "(The upcoming speech) shows the president is in this fight for keeps - he's not backing off. He's doing just the right thing to take the momentum back."

Obama finds himself in the awkward position of fending off sharp criticism from centre-right minority Republicans firmly opposed to creating new government programmes to increase federal spending, but without risking alienation of his base among leftwing Democrats, whom he has already angered by downplaying the importance of the so-called public option in his overall plan.

Obama has not attached himself to any specific proposal in Congress, but recent signals from the White House that he is prepared to drop the public option has drawn criticism from the more hardened members of his party.

The public option is designed to provide government-run medical insurance to some of the nation's 46 million people who are without coverage, while competing with private insurers to get costs down. Some Republicans assail it as socialist and un-American, and some moderate Democrats are sceptical.

Obama plans to address a joint session of Congress on Wednesday - one day after lawmakers return - to get a fresh start on the debate, which could still drag out for weeks or months. The president has stated he wants legislation passed by the end of the year.

History is not on Obama's side.

Many of his predecessors failed in attempts to enact major health- care reforms, in part because of stiff resistance put up by the powerful health-care and insurance lobbies. Bill Clinton's unsuccessful effort in the 1990s was a major blow to his young presidency.

The last president to push through substantial changes was Lyndon Johnson, who set up Medicaid and Medicare in 1965 to help the poor and senior citizens.

The debate has taken a political toll on Obama.

Recent opinion polls give the lowest job-approval ratings of his presidency. Although hovering around a solid 53 per cent approval overall, a majority of respondents have unfavorably viewed how Obama has handled the health-care issue.

An inability to pass significant health reforms could sap Obama of the political muscle he needs to push through other key reforms on issues like climate change, financial regulation and closing the prison for terrorist suspects at Guantanamo Bay.

Meanwhile, a compromise effort continues among a bipartisan group of senators. Legislators in the Senate Finance Committee are currently working on a deal that could create government-backed co- operatives in lieu of the public plan.

The United States has the costliest health system in the industrialized world, consuming about 16 per cent of economic output. Legislators have been haggling for months over how best to rein in costs and extend coverage. (dpa)