Senators must overcome disagreements on funding for two Obamacare stabilization bills to get the legislation ready to add to a must-pass spending bill next month.

Democrats are pushing to add money to boost income-based subsidies to a bill co-sponsored by Sen. Lamar Alexander, R-Tenn., and Sen. Patty Murray, D-Wash., to lower the cost of insurance on Obamacare's marketplaces, a Democratic aide said. The bill would restore Obamacare insurer payments in return for states getting more latitude to waive Obamacare insurer regulations.

Some Republicans are doubtful that more money can be added to the legislation.

Democrats also want to restore advertising and outreach funding cut by the Trump administration for open enrollment last year. The administration cut funding by 90 percent to $10 million for the 2018 open enrollment period, which ended last year, from $100 million for the 2017 open enrollment period under the Obama administration.

They also hope to stop President Trump from selling “junk” insurance plans that provide skimpy coverage and drive up costs for people with pre-existing health conditions, the aide said.

The goal is to bolster the bills to help compensate for the loss of the individual mandate, Obamacare's requirement for everyone to have health insurance, the aide said. The tax reform bill that passed last year repealed the mandate starting in 2019, and the Congressional Budget Office projects the loss will cause up to 13 million people to not get insurance over the next decade and raise premiums 10 percent each year.

The aide also pointed to Trump's pursuit of regulations to expand access to cheap, low-quality plans. The Trump administration is expected to release new regulations to expand the duration of short-term plans from 90 to 364 days. It already released regulations to allow more people to band together to buy association health plans.

But the aide did not specify how much new funding Democrats hope to add to the bill. And it's not clear that any additional funding would make it into the final legislation.

Alexander said he and Murray are discussing changes to the bill now.

“We need to come to a prompt conclusion on our proposal so it can be part of the omnibus,” Alexander said, referring to the two-year budget bill that the senators hope to use as a vehicle to pass the bills. “We are gonna be trying to do that in the next few days.”

Murray said that she is talking with Alexander on changes she wants to the bills.

Sen. Susan Collins, R-Maine, who is behind one of the two bills, added that she didn’t think it was feasible to add more money for subsidies to the Alexander-Murray legislation.

Collins and Sen. Bill Nelson, D-Fla., sponsored legislation to give states $10 billion over two years to set up a reinsurance program that covers the highest medical claims from Obamacare insurers. The companies in turn would lower premiums overall.

Congress is expected to pass a deal outlining a two-year budget on Thursday with a short-term spending deal that extends government funding until March 23.

Congress in March will try to pass a long-term spending bill called an omnibus that appropriates the funding. The senators supporting the two bills hope to add them to that omnibus.

Washington Examiner Senior Healthcare Writer Kimberly Leonard contributed to this report.