(CN) - The number of Republican senators who say they are not ready to vote for the new GOP health care bill rose to five on Friday, increasing the odds the measure will never be passed.
Four senators: Ted Cruz of Texas, Ron Johnson of Wisconsin, Mike Lee of Utah and Rand Paul of Kentucky announced their opposition to the bill on Thursday.
Sen. Dean Heller, of Nevada, joined the opposition on Friday, saying "it's going to be very difficult for me to say yes."
The first four senators to announce their opposition said in a statement Thursday that they are open to negotiation before the full Senate considers the measure.
The four said there are provisions that are an improvement to the current health care system. But they add that the measure fails to accomplish what they have promised to their constituents, "to repeal Obamacare and lower their health care costs."
GOP leaders hope to vote on the bill next week but can only afford two defections from the 52 Senate Republicans.
"It just doesn't sound conservative," Paul told reporters on Thursday. "So really it is about the details. Somebody's going to have to look at this bill and say we're going to make it more like repeal and less like we're keeping Obamacare."
But if the four are at least willing to hold the door open to voting for the health care bill, Heller, who many consider the Senate Republican most at risk in the 2018 midterm election, doesn't appear to have much latitude to change his mind.
"I cannot support a piece of legislation that takes insurance away from tens of millions of Americans and hundreds of thousands of Nevadans," Heller said.
Despite the defections, Sen. John Cornyn, the Republican responsible for rounding up his party's votes on bills, said party leadership still plans on holding a vote on the bill next week. He said Republicans may need to make changes to the bill to bring on board conservative defectors and that those changes could be offered in a new piece of legislation as late as Tuesday.
The Congressional Budget Office still needs to complete its analysis of the bill, which could happen on Monday, and offer "tweaks and changes" as needed to deal with new language in the legislation, Cornyn told reporters Thursday.
"This is hard, there's no question about it," Cornyn said of Republican holdouts on the bill. "It makes it even harder when you have to do it purely as a one-party exercise because of the reconciliation process. But that's not an excuse for failure in my view."
Senate Republicans released their long-awaited bill to repeal and replace the Affordable Care Act Thursday morning, proposing to cut Medicaid for low-income Americans and erase Obama-era tax increases the Democratic president imposed on the wealthy to finance his expansion of coverage.
The proposed bill would also provide less-generous tax credits to help people buy insurance and would allow states to get waivers for some of the coverage standards imposed by the Act.
And it would end the tax penalties the Act imposed on people who decided not to insurance and on large companies who don't offer coverage to their employees.