Sen. Susan Collins, a key centrist Republican from Maine, will vote Wednesday in favor of advancing a bill that would overhaul the tax code, despite the problems she still has with the bill.

Collins told reporters that she is still concerned about the bill's provision to repeal Obamacare's individual mandate penalty, but that she has received assurances from leadership that the Senate will take up a bipartisan healthcare bill known as Alexander-Murray, as well as a bill she introduced that would fund a reinsurance program to reduce premiums.

Republicans think those provisions would help offset the effects of language in the tax bill that would repeal the individual mandate penalty.

"I still would prefer that the individual mandate [repeal] were not in the bill," Collins said. "It's not that I'm a fan of the individual mandate. I don't think we should be fining people who choose not to buy insurance, but it complicates this whole issue and when you pull one piece of the Affordable Care Act out it has an impact on premiums and that's why Alexander-Murray and Collins-Nelson are so important."

Senate Majority Leader Mitch McConnell has committed to hold a vote on Alexander-Murray, Collins said, though the way it receives a vote has still not yet been decided. One possible idea was for it to be part of a continuing resolution, she said, adding that the commitment was it would be put on a must-pass bill.

The House has not yet committed to supporting the Alexander-Murray deal that would appropriate funding for two years for cost-sharing reduction subsidies and give states more flexibility on how to implement Obamacare. President Trump has said he would support the measure in exchange for the tax bill including the repeal of the individual mandate penalties that obligate Americans buy health insurance or pay a fine.

A Congressional Budget Office report published Wednesday found that even if Congress passes Alexander-Murray while repealing the individual mandate penalties, 13 million more people will still become uninsured. Republicans have disputed the findings and CBO officials have been working on ways to evaluate how they measure the impact of the individual mandate, though it will not change ahead of the tax vote.

Collins said she had glanced at the CBO report but noted it assumed a baseline with the cost-sharing reduction payments included.

"They're not being paid. They've been suspended by the president," she said. "That's the whole point of the Alexander-Murray bill is to ensure that the cost-sharing reductions are paid. So the CBO letter really truly makes no sense whatsoever."

Collins did not yet say whether she planned to support the passage of the tax bill, and said she had filed several amendments, including an amendment that fixes a provision of the bill that would prohibit public employees from making catch-up contributions to their retirement accounts.

Asked whether she would support the bill only if they included her amendments, Collins replied: "We're doing this one step at a time. Some of these are higher priorities than others."

During the debate over healthcare legislation this summer, Collins joined Sen. Lisa Murkowski, R-Alaska, to vote against a motion to proceed on a bill that would have repealed and replaced portions of Obamacare. She subsequently voted against a "clean repeal" bill that Congress passed previously in 2015 without her support, which former President Barack Obama vetoed at the time.

She voted against the "repeal and replace" bill that Senate Republicans wrote, and voted against a "skinny repeal" bill that included the repeal of the individual mandate. The "skinny repeal" bill ultimately sank when two other Republicans, Murkowski and Sen. John McCain of Arizona, sided with all Senate Democrats to vote against it.

Neither McCain nor Murkowski have publicly indicated whether they will support the motion to proceed on the tax bill.