MIAMI (Reuters) - President Barack Obama said on Thursday (Oct 20) that his departure from office in January might be what it takes to begin to heal the political scars over Obamacare and allow for needed fixes to his signature healthcare law.

The 2010 Affordable Care Act tipped off a long and bitter political and legal battle between the White House and Republicans in the US Congress who said the 2010 law creates unwarranted government intervention in personal healthcare and private industry.

Republicans have been quick to highlight a recent barrage of negative headlines about rising health insurance premiums and shrinking doctor networks for people participating in subsidised insurance plans offered under the law.

Obama acknowledged the law is not working perfectly, but said the problems could be fixed by legislation, encouraging lawmakers to create a government-run health insurance option to help US states where there is little or no competition among private insurers.

"Maybe now that I'm leaving office, maybe Republicans can stop with the 60-something repeal votes they've taken and stop pretending that they have a serious alternative ... and just work with the next president to smooth out the kinks," he said in a speech at Miami Dade College.

"They can even change the name of the law to Reagancare, or Paul Ryan care," Obama said, evoking the name of the Republican speaker of the House of Representatives.

"I don't care. I just want it to work."

But Ryan, in a written response, said he would continue to seek to repeal and replace the law. "At this point, one thing is clear: This law can't be fixed," Ryan said.

Obama was later slated to headline a rally in Florida, a battleground election state, for Hillary Clinton, the Democratic candidate in the Nov 8 presidential election.

Clinton has said she would add a public option and expand tax incentives for healthcare costs. Republican nominee Donald Trump has pledged to repeal and replace the law.

The government forecasts 13.8 million people will sign up for Obamacare plans in 2017, up 1.1 million from 2016.

There are 10.7 million uninsured people who are eligible for the exchanges but have not enrolled, and about 40 per cent of those are young, Health and Human Services Secretary Sylvia Burwell said on Wednesday.

Obama said that nationwide, not enough young and healthy people have signed up to provide a revenue stream that offsets the costs of covering members with serious illnesses.

As a result, several big insurers, including UnitedHealth Group Inc, Aetna Inc and Humana Inc, are pulling out of the online marketplaces selling the subsidized plans, citing bigger-than-expected financial losses.

Monthly premium prices have climbed, which further discourages some people from signing up. "Next year will tell whether those are growing pains, or they are more serious issues," Drew Altman, chief executive of the Kaiser Family Foundation, said in an interview.

Analysis conducted by the nonpartisan foundation suggests at least 16 million people need to enroll before the online Obamacare insurance marketplaces stabilise.

Obama said expanding insurance coverage for millions of people and reforming the healthcare system was a key reason he ran for office. He said he gets letters from Americans every day thanking him for the difference it has made in their lives.

The law cut the number of uninsured Americans from 49 million in 2010 to 29 million in 2015.

Much of the decline is due to the law's provision allowing states to expand Medicaid health coverage for the poor.

The law also prohibited insurance companies from denying coverage to Americans for existing medical problems, and allowed parents to keep children insured on their health plans until age 26.

Some health policy experts on both the political left and right say Congress may be more receptive to bipartisan efforts to fix the Affordable Care Act after Obama leaves office. Some Republican governors who refused to expand Medicaid may also be more willing to do so after the election - a change that would expand coverage for about 4 million people.

"I think the piece of Obamacare that people don't like is Obama," Kathleen Sebelius, Obama's former Health and Human Services secretary, who oversaw the programme's launch, said in an interview.

"This has become a very personal battle about this president, which is I think really unfortunate."