U.S. President Barack Obama speaks to a joint session of Congress on health care at the U.S. Capitol in Washington on Wednesday. (Jason Reed/Associated Press)

U.S. President Barack Obama urged politicians Wednesday to end decades of inaction and strike a deal on a national health-care plan.

In a televised speech to a joint session of Congress on Wednesday evening, Obama said the time for partisan bickering is over.

"Now is the season for action," he said. "Now is when we must bring the best ideas of both parties together and show the American people that we can still do what we were sent here to do. Now is the time to deliver on health care."

Obama has made reforming the $2.5-trillion U.S. health-care system a priority in his first year of office, but the process has sparked angry debate.

Wednesday's speech is seen as a crucial test for the president, who must accommodate moderate Democrats and Republicans without losing the support of reform-minded members of his own party who are determined to have some form of government-run health insurance.

In his speech, Obama said the proposed health-care reform law won't mean changes for Americans who already have health insurance.

"What this plan will do is to make the insurance you have work better for you," he said, adding that it would be illegal for insurance companies to deny someone coverage due to a pre-existing condition.

He said the government would place limits on how much people can be charged for out-of-pocket expenses, and insurance companies will be required to cover routine checkups and preventive-care procedures such as mammograms and colonoscopies.

For Americans without coverage, the White House is proposing a new insurance exchange — "a marketplace where individuals and small businesses will be able to shop for health insurance at competitive prices," Obama said.

He said his plan will cost around $900 billion US over 10 years, "less than we have spent on the Iraq and Afghanistan wars, and less than the tax cuts for the wealthiest few Americans that Congress passed at the beginning of the previous administration."

Representative Charles Boustany, a Republican from Louisiana and also a heart surgeon, said the country wants Obama to instruct Democratic congressional leaders that "it's time to start over on a common-sense, bipartisan plan focused on lowering the cost of health care while improving quality."

"Replacing your family's current health care with government-run health care is not the answer," said Boustany.

Reforming health care is Obama's chief priority, but it is apparently costing him lots of political goodwill. An AP-GfK survey hours before the speech indicated that public disapproval of Obama's handling of health care had risen to 52 percent, an increase of nine percentage points since July.

With files from The Associated Press