House Democrats slammed Republicans for approving new rules that they say hide the true cost of repealing Obamacare.

The House passed via a 234-193 vote on Tuesday a package of rules governing the 115th Congress. Among the rules are the prohibiting of the nonpartisan Congressional Budget Office from reviewing whether any bill repealing Obamacare would increase spending over a decade.

Democrats said the move tucked into the package is an attempt to hide the cost of an Obamacare repeal.

"The party that claims to be fiscally responsible is now looking to change the rules of the House so it can be fiscally reckless in its dangerous assault on the Affordable Care Act," said Rep. Frank Pallone, D-N.J., on the House floor Tuesday.

He said that House Republicans "know that repealing the Affordable Care Act will increase direct spending and the deficit by $3 trillion and the cynical rules proposal shows that Republicans want to hide the true costs of their repeal plans."

The rules package said that the director of the budget office should prepare an estimate of whether any bill would cause, relative to the current law, a boost in spending in excess of $5 billion over the next four decades.

However, the requirement doesn't apply to any bill, joint resolution or amendment that would repeal Obamacare.

House Minority Whip Steny Hoyer, D-Md., said the budget office has estimated that full repeal of the law could increase the deficit by $137 billion.

Republicans are admitting "in their own rules that their proposal to repeal the Affordable Care Act will be devastating to the federal deficit and the national debt," he said on the House floor.

Republicans shot back that Obamacare has been a failure.

"I'm still stunned that Republicans are blamed for the failures of Obamacare when in fact it's Obamacare that we're going to amend and we are going to change," said Rules Committee Chairman Rep. Pete Sessions, R-Texas, on the floor.

Republicans started their efforts to repeal Obamacare on Tuesday with Sen. Mike Enzi, R-Wyo., introducing a budget resolution that sets spending levels for the next decade.

The resolution directs committees in the House and Senate to start crafting legislation to repeal Obamacare through a procedural move called reconciliation, which enables Republicans to bypass a filibuster in the Senate and approve repeal via a majority vote.

The Senate parliamentarian must approve whether a bill that seeks to use reconciliation before it hits the Senate floor. A reconciliation bill must address only budgetary and spending levels.

The Senate approved an Obamacare repeal bill in 2015 using reconciliation. As a result, the bill gutted major parts of Obamacare such as the law's taxes and mandates but left in place requirements on what plans insurers could offer on the individual market, which is for people who don't get insurance through their job.

Obamacare created a slew of new rules for the types of plans an insurer could sell on the individual market, which includes Obamacare's marketplaces. Among the rules are that insurers can't deny coverage to people with pre-existing conditions and that each plan had to include certain essential benefits.