President-elect Donald Trump has said he plans to repeal and replace the Affordable Care Act (ACA) as soon as his health secretary pick is confirmed.
In his first news conference since July, Mr Trump said he would submit a plan to repeal and replace the 2010 law “essentially simultaneously”.
Senate Republicans have started a process to repeal parts of the law.
They voted 51-48 overnight to instruct key committees to draft the corresponding legislation.
But there seems little consensus on what would replace Obamacare.
Mr Trump’s remarks clash with congressional Republicans’ plan to repeal the law, but delay the process to pass legislation on a substitute for up to three years.
The president-elect said he would like to see President Barack Obama’s signature healthcare law, also known as Obamacare, repealed and replaced “probably the same day, could be the same hour”.
He insisted his administration would have a plan in place as soon as Representative Tom Price, his nominee for Health and Human Services Secretary, is confirmed.
Mr Price’s hearings are due to begin next week.
Mr Trump did not offer any details on his vision to replace the healthcare law, but argued it was “imploding” and Republicans would do “a tremendous service” for Democrats by replacing it.
He added his plan would be “far less expensive and far better”.
Republicans plan to dismantle Obamacare through a budget reconciliation bill.
“We must act quickly to bring relief to the American people,” said Senate Majority Leader Mitch McConnell.
The US Chamber of Commerce, which is the country’s largest business lobby group, warned on Wednesday it could be a mistake to quickly repeal Obamacare without developing a replacement insurance plan.
A day earlier, the Health and Human Services Department said more than 11.5 million Americans had signed up for plans in this open-enrolment period, the highest such figure in the bill’s history.