The influential conservative groups Heritage Action and FreedomWorks are urging lawmakers to vote "no" on the new House plan to open the government and raise the debt ceiling.
The conservative groups both said they will "key vote" a bill that was expected to hit the House floor Tuesday night.
Heritage Action said the deal would do nothing to stop the implementation of ObamaCare.
"Unfortunately, the proposed deal will do nothing to stop ObamaCare’s massive new entitlements from taking root — radically changing the nature of American healthcare," the group said in a statement.
Matt Kibbe of FreedomWorks urged the group's members to put pressure on House Republicans to reject the plan.
“Last month, Republicans in the House took a principled stand to defund this law, offering merely to delay it for a year. President Obama, Senator Harry ReidHarry Mason ReidThe Hill's 12:30 Report - Presented by Connected Commerce Council - Biden faces reporters as his agenda teeters Biden hits one-year mark in dire straits 'All or nothing' won't bolster American democracy: Reform the filibuster and Electoral Count Act MORE, and congressional Democrats have refused to consider any changes to the unpopular healthcare law,” Kibbe wrote.
“Now House Republicans are contemplating an amendment that would life the debt ceiling and fund ObamaCare in return for essentially nothing. It's basically a full surrender to the intransigent left and another win for the insulated Beltway elites.”
The House Rules Committee postponed a meeting on the latest version of the rapidly changing proposal, which would extend government funding to Dec. 15 and the debt ceiling through Feb. 7.
In the new version of the bill, GOP leaders dropped a push to two-year delay of a medical device tax and tacked on a provision that would strip employer contributions lawmakers get for health insurance under ObamaCare so that it also applies to staff.
Another conservative group, Club for Growth said is has "not taken a position yet" on the bill.
"Despite overruling OPM’s congressional exemption, the proposed plan will do absolutely nothing to help Americans who are negatively impacted by ObamaCare," the group said.
"Premiums will continue to skyrocket, cancellation notices will still arrive in the mail, employers will continue reducing hours and bureaucrats will continue reaching deeper and deeper into our health care decisions."
On Jan. 1 the healthcare law's new entitlements are expected to start.
One House Republican said Tuesday that the shorter deadline — a Senate proposal pushes the continuing resolution to Jan. 15 — is aimed at limiting contraception coverage under the law.
"It boils down to conscience protections that basically become compromised on the first of January, and that's bothersome to a lot of people," Rep. Steve WomackStephen (Steve) Allen WomackArkansas legislature splits Little Rock in move that guarantees GOP seats Funding fight imperils National Guard ops Overnight Defense: 6B Pentagon spending bill advances | Navy secretary nominee glides through hearing | Obstacles mount in Capitol security funding fight MORE (R-Ark.) said.
"It concerns me but it concerns a lot of people in our conference that a provision of the Affordable Care Act goes into effect and that is a violation of the conscious beliefs of a lot of members of our party."
Heritage argues that taxpayers will spend $48 billion in 2014 – and nearly $1.8 trillion through 2023 — on the programs.
Mike Lillis and Peter Schroeder contributed to this story.