The formulation of a healthcare bill suitable to both sides has so far proved elusive, despite the efforts of a six-member bipartisan panel tasked with drafting a new policy.
Obama has argued that his plan is aimed at providing more affordable health coverage to 46 million uninsured Americans.
His speech is designed to re-take control of the debate after his plans for change came under fire by Republicans and conservative groups.
They allege that Obama's package amounts to a socialist takeover of the US healthcare system, and that spending $1 trillion on the overhaul is irresponsible at a time when the US is holding its highest-ever budget deficit.
Rob Reynolds, Al Jazeera's corrrespondent in Washington DC, said: "Obama has to refute some of the misleading information and outright falsehoods that have circulated about the healthcare proposals; he has to project a sense of leadership, because he has been heavily criticised for not providing enough details on the package.
"This speech is being portrayed, at least in the media, as a pivotal moment - a turning point in his presidency."
Robert Gibbs, the White House spokesman, said Obama would discuss the high level of medical malpractice lawsuits, which Republicans say have pushed up insurance premiums.
"The president will talk about meaningful malpractice reform tonight," he told the Fox news network.
"What I hope that does is cause Republicans to understand that we're close to getting something truly significant done for the American people, truly significant for those struggling with the high cost of health insurance."
Gibbs emphasised that Obama is seeking a government-run public insurance option alongside private insurers to provide "choice and competition".
Although the Democrats have control of the upper and lower houses of congress, failure to win broad support on changes to the healthcare system could weaken Obama politically and affect other aspects of his policy proposals.
His attempt to reform the US healthcare system has so far gone further than former president Bill Clinton's move to overhaul medical insurance 16 years ago, Reynolds said.
"His healthcare proposals have gotten further than Clinton's did. Obama has four of the relevant committees in congress to sign off on a plan, and he is waiting for a fifth committee, which is really the crucial one. In that sense, he has momentum that Clinton never had," Reynolds said.
But should Obama fail to win broad-based support for his plan, it could negatively affect other items on his policy agenda.
"There is the cap-and-trade legislation coming up [on climate change]; if Obama fails here [on healthcare reform], he will be seen as weak," Reynolds said.
"In the foreign affairs field, the president is expecting to unveil his proposals for a Middle East peace agreement. If Obama is severely weakened on the domestic front, all the actors from the Israeli and Palestinian government, as well as Hamas and Iran, will be watching ... and could adjust their strategies accordingly."