US President Donald Trump has threatened to end government payments to health insurers if congress does not pass a healthcare bill.

In a Twitter message on Saturday, Trump said: “if a new HealthCare Bill is not approved quickly, BAILOUTS for Insurance Companies and BAILOUTS for Members of Congress will end very soon!”

Trump’s comment came after Senate Republicans failed to repeal parts of the Affordable Care Act, former president Barack Obama’s signature healthcare bill, on Friday.

The first part of Trump’s tweet appeared to be referring to the approximately $US8 billion in cost-sharing reduction subsidies paid by the federal government to insurers to lower the price of health coverage for low-income individuals.

The second part of the tweet appeared to be a threat to end the employer contribution for members of congress and their staff who were moved from the normal federal employee healthcare benefits program on to the Obamacare insurance exchanges as part of the 2010 healthcare law.

The Obama administration had ruled that these contributions could continue, flowing through the District of Columbia insurance exchange.

Many insurers have been waiting for an answer from Trump or lawmakers on whether they will continue to fund the annual government subsidies. Without assurances, many insurers plan to raise rates an additional 20 per cent by an August 16 deadline for premium prices.

With Republican efforts to dismantle Obamacare in disarray, hundreds of US counties are at risk of losing access to private health coverage in 2018 as insurers consider pulling out of those markets.

In response, Trump on Friday again suggested that his administration would let the Obamacare program “implode”.

He has weakened enforcement of the law’s requirement for individuals to buy insurance, threatened to cut off funding and sought to change plan benefits through regulations.

Meanwhile, some congressional Republicans were still trying to find a way forward on healthcare reform.

Senator Lindsey Graham said in a statement issued late on Friday that he and two other Republican senators, Dean Heller and Bill Cassidy, met with Trump after the defeat to discuss Graham’s proposal to take tax money raised by Obamacare and send it back to the states in the form of healthcare block grants.

Graham said the move would end Democrats’ drive for a national single-payer healthcare system by putting states in charge.