Senate Republican leaders are expected to move forward with plans to hold a vote on health care legislation this week, even though lawmakers have complained they are being left in the dark about what exactly they would be voting on.

Majority Leader Mitch McConnell has said he will forge ahead with a strategy to put a measure passed earlier this year by the House up for a procedural vote, with the intention of allowing senators to later vote on amendments that would replace it with other versions of the bill wholesale or in part.

"We are still on track ... to have a vote early this week," a spokesman for the Kentucky Republican was quoted by The Washington Post as saying Sunday. "The Senate will consider all types of proposals, Republican and Democrat."

Confusion over what they would be voting for has several senators balking and comes amid questions about whether Republicans have enough support to even pass a procedural vote that would begin debate.

Senators "don't know whether we're going to be voting on the House bill, the first version of the Senate bill, the second version of the Senate bill, a new version of the Senate bill or a 2015 bill that would have repealed the Affordable Care Act now and then said that somehow we'll figure out a replacement over the next two years," Sen. Susan Collins told CBS' "Face the Nation" on Sunday.

Collins, R-Maine, has objected to each proposal put forward by the Senate, primarily over cuts to Medicaid, and has said she would vote against opening debate. On Sunday, she objected to the secrecy surrounding the process.

"I don't think that's a good approach to facing legislation that affects millions of people and one-sixth of our economy," she said.

Sen. Rand Paul, R-Ky., has opposed each of the Senate's replacement plans and expressed frustration with the process, suggesting that he was not confident that McConnell's plan met his requirement of voting to move toward a more complete repeal, rather than one of the other options that has been proposed.

Paul told CNN on Sunday that he would be willing to vote to move to debate "if we're proceeding to the clean repeal vote."

"The real question is, what are we moving to? What are we opening debate to? Last week, Senate leadership said it would be a clean repeal ... and I think that's a good idea," he said on CNN on Sunday.

That plan – favored by some conservatives and suggested by McConnell last week – would likely fail to attract the requisite 50 votes, with Collins, along with Sens. Lisa Murkowski of Alaska and Shelley Moore Capito of West Virginia on record against it.

Some clarity is likely to come Tuesday, after McConnell holds a weekly meeting with his conference.

The decision was further complicated by the Senate parliamentarian, who on Friday concluded that many aspects of the Republicans' replacement plan would not qualify for consideration under special budget reconciliation rules that allow legislation to move forward with a simple majority, not the 60 votes normally needed for a motion to proceed.

Among the provisions preliminarily found to have violated the Byrd rule – which limits the reconciliation process to be used on laws that directly affect the federal budget – were a measure to defund Planned Parenthood, a "continuous coverage" lockout clause that bars people who have let their insurance coverage lapse from buying a new plan for six months, and a phase-out of essential benefit requirements for Medicaid plans.