The White House doesn't put much stock in an estimate from the Congressional Budget Office Tuesday that said premiums would jump by 20 percent if President Trump cuts off payments to Obamacare insurers.

The CBO estimated Tuesday that Obamacare premiums would rise by 20 percent in 2018 and 25 percent in 2020 if Trump cuts off cost-sharing reduction payments to insurers. The report drew a sharp rebuke from the White House.

"Regardless of what this flawed report says, Obamacare will continue to fail with or without a federal bailout," said Ninio Fetalvo, a White House spokesman. "Premiums are accelerating, enrollment is declining, and millions are seeing their options dwindling. This disastrous law has devastated the middle class and must be repealed and replaced."

Some insurers have blamed their requests for big increases in premiums next year on uncertainty from the Trump administration over the payments and the future of the law. Other factors include poor enrollment in the law's exchanges and a sicker-than-expected enrollee population.

Other groups such as the nonpartisan Kaiser Family Foundation have predicted a 20 percent premium bump if the insurer payments are not made.

The cost-sharing payments reimburse insurers for reducing co-pays and deductibles for low-income Obamacare customers, which insurers are required to do under the law.

The federal government is expected to pay about $7 billion this year in cost-sharing payments.

Trump has flirted with cutting off the payments as part of a strategy to let Obamacare "implode" to get Democrats to work with Republicans to reach a healthcare deal.

Ninio said that no decision has been made yet on the payments for 2018.

The White House did not offer a reason as to why it says the report is flawed, but an aide told the Washington Examiner that the agency has been wrong repeatedly.

They noted that CBO was off the mark on Obamacare, estimating that 24 million people would enroll in Obamacare's exchanges in 2017 when the actual number is less than half that.

Meanwhile, the Senate is expected to try to reach a bipartisan deal to make the payments for 2018. Sen. Lamar Alexander, R-Tenn., who is helping spearhead the effort, hopes to get funding for the payments by the end of September.

The deadline for insurers to sign contracts for 2018 plans is Sept. 27. Open enrollment is expected to start Nov. 1.