Barack Obama's subsidized healthcare reforms will cost taxpayers an extra $10billion next year, a new report has found.

Research by the Center for Health and Economy has found the sum will be needed to cover double-digit premium hikes.

It comes as the Republican-led Congress prepares to repeal Obamacare and replace it with a GOP alternative, although details of what this will consist of are yet to be confirmed.

Barack Obama's subsidized healthcare reforms will cost taxpayers an extra $10billion next year, the Center for Health and Economy has found

The new study estimates that the cost of premium subsidies under the Affordable Care Act will increase by $9.8billion next year, rising from $32.8billion currently to $42.6billion.

The average monthly subsidy will increase by $76, or 26 per cent, from $291 currently to $367 in 2017, researchers found.

Currently more than eight in ten consumers buying private health insurance through HealthCare.gov and state markets receive tax credits from the government to help pay their premiums.

Those subsidies are designed to rise along with premiums, shielding consumers from sudden increases - but the bill ultimately gets passed on to taxpayers.

Shortly before Election Day, the administration revealed that premiums for a midlevel benchmark plan on HealthCare.gov would jump by an average of 25 per cent next year.

The Republican-led Congress is expected to repeal Obamacare and replace it with a GOP alternative, although details of what this will consist of are yet to be confirmed

Administration officials are touting the premium subsidies as they race to sign up as many people as possible before open enrollment ends Jan. 31, about a week after Obama leaves the White House.

Adverts for HealthCare.gov say most consumers can find subsidized coverage for as little as $50 to $100 a month.

Republicans are planning a multistep process to first repeal the health law and replace it later.

The findings could affect how Republicans design future subsidies that would be part of their replacement legislation. A limit on assistance is more likely to appeal to them.

Economist Douglas Holtz-Eakin, founder of the nonpartisan Center for Health and Economy, said 'you get a premium increase, you pour more money in'

Under current law, economist Douglas Holtz-Eakin, founder of the nonpartisan Center for Health and Economy, said 'you get a premium increase, you pour more money in'.

He added: 'The concern is that will feed more premium increases.'

Holtz-Eakin, a longtime GOP advisor, predicted that Republicans would take a different approach.

After reviewing the study, the Obama administration said that despite the increase in premiums, the health care law is still helping to reduce federal deficits, keeping the program affordable for taxpayers. The law also raised taxes and cut Medicare spending.

'The Affordable Care Act is covering 20 million Americans, and 2017 marketplace premiums remain on par with the Congressional Budget Office's November 2009 projections,' spokesman Aaron Albright said.

A health economist who also reviewed the study said it shows that the law is working as it was intended to.

'Since the premiums for 2017 are a lot higher than for 2016, it's no surprise that premium tax credits would go up as well,' said Paul Ginsburg, director of the Brookings Institution health policy center.

'The premiums in 2015 and 2016 appear to have been unduly low.'

Adverts for HealthCare.gov say most consumers can find subsidized coverage for as little as $50 to $100 a month

Obama's law has helped drive the nation's uninsured rate to a historic low of about nine per cent. It offers subsidized private health insurance to people who don't have access to job-based coverage, along with a state option to expand Medicaid for low-income people.

Insurers say the spike in premiums is due to lower-than-projected enrollment, patients who turned out to be sicker than expected, people gaming the system to get coverage only when they need medical care, and a premium stabilization system that has not worked as intended.

The administration says the higher premiums are a one-time market correction, and not a sign that the law's insurance markets are slipping into a 'death spiral' of rising premiums and declining enrollment.

Although Congress will begin the repeal debate soon after it convenes in January, immediate changes that would affect coverage for 2017 appear to be highly unlikely.