Senate Republicans said Thursday they won't vote on the House-passed bill to repeal and replace Obamacare, but will write their own legislation instead.

A Senate proposal is now being developed by a 12-member working group. It will attempt to incorporate elements of the House bill, senators said, but will not take up the House bill as a starting point and change it through the amendment process.

"The safest thing to say is there will be a Senate bill, but it will look at what the House has done and see how much of that we can incorporate in a product that works for us in reconciliation," said Sen. Roy Blunt, R-Mo.

"We are going to draft a Senate bill," added Sen. Chuck Grassley, R-Iowa. "That is what I've been told."

The working group has been meeting for weeks, said Senate Majority Whip John Cornyn, R-Texas, a member of the group.

"What we have to do is build a consensus among our conference and that is what the working group is designed to do," Cornyn said. "To get to a compromise we can agree to and then present it to the larger conference."

Cornyn said there is "really no deadline" for the group to produce a bill. "We are just working toward getting 51 votes," he said.

Majority Leader Mitch McConnell, R-Ky., did not indicate how the Senate would act. "As Congress considers this legislation, the administration will continue working to deliver relief and stabilize health markets, and Congress will continue to act on legislation to provide more choices and freedom in healthcare decisions," he said.

"Senate consideration will be scheduled following the completion of procedural and budgetary scorekeeping reviews," a top GOP aide added.

"The status quo of Obamacare is unacceptabe," addedMcConnell spokesman David Popp said. "It has failed the American people and must be repealed and replaced. As the Senate continues its work on fixing the broken promises of Obamacare, Senators from throughout the Conference have been working on solutions. Those meetings and efforts continue, including chairmen of the relevant committees and leadership. They will continue to have regular updates with the entire conference so the Senate can continue to move expeditiously on the work ahead as it considers the House-passed legislation."

The working group is made up of members of the three committees that have jurisdiction over healthcare: Finance, Budget and the Health, Education, Labor and Pensions panel.

Cornyn said Sen. Susan Collins, R-Maine, who has co-authored her own Obamacare replacement measure, "has been an integral part of the discussions."

Collins, who is not a member of the working group, has written a proposal with Sen. Bill Cassidy, R-La., that would allow states to keep Obamacare or provide an alternative that would entail auto-enrolling residents in a basic health insurance and pharmacy plan.

Cornyn said talks so far have centered around what the House might do, amid some doubts that the House would ever be able to pass a bill.

That changed Thursday, when House GOP lawmakers passed their Obamacare repeal and replace plan that allows states to request waivers for the Obamacare mandates and provides money and a high-risk pool for those with pre-existing conditions.

"It was kind of a moot issue if the House wasn't going to be able to pass a bill, and now they have and I'm proud of them for doing it," Cornyn said. "Now it's up to us to pass a bill 51 senators can agree to."