Rep. Mo Brooks of the hard-line Freedom Caucus told CNBC on Friday the House Obamacare replacement plan is the worst bill he's seen in 30 years of public service.
"It's not a repeal. It's a marketing ploy," he said.
Brooks is calling for a straight repeal of former President Barack Obama's 2010 health-care law, despite the long odds of ever getting the Senate to go that far.
"We can either go bankrupt as a country or do the right thing," he said.
Meanwhile, White House budget director Mick Mulvaney told CNBC in a later interview the ultimatum he delivered from the president was to all House Republicans.
No one group, such as the Freedom Caucus, was being singled out, said Mulvaney, who had been a member of that conservative group when he was a congressman from South Carolina.
Mulvaney said he's not sure whether Republicans have enough votes for passage but stressed "the president has his offer on the table."
Brook said he won't be swayed by the White House or his fellow House Republicans.
One of his GOP colleagues, Rep. Bill Johnson, told "Squawk Box" earlier on Friday: "My Freedom Caucus friends have helped make this bill stronger. And I appreciate that."
But the Ohio Republican, who supports the AHCA, said he hopes conservative holdouts vote for the bill in the end because it's the best way to unleash competition.
"We're grossly underestimating what's going to happen when America's markets respond to getting the federal government out of the way," Johnson said.