Rubio has formed a conservative coalition in the Senate with Sens. Mike LeeMichael (Mike) Shumway LeeWhatever you think the Alabama special election means, you’re probably wrong How the effort to replace ObamaCare failed Overnight Regulation: Trump temporarily lifts Jones Act for Puerto Rico | Bill would exempt some banks from Dodd-Frank | Senators unveil driverless car bill MORE (R-Utah), Ted CruzRafael (Ted) Edward CruzWhatever you think the Alabama special election means, you’re probably wrong This week: Congress gets ball rolling on tax reform Week ahead: Senators work toward deal to fix ObamaCare markets MORE (R-Texas) and Rand PaulRandal (Rand) Howard PaulHouse bill set to reignite debate on warrantless surveillance Authorizing military force is necessary, but insufficient GOP feuds with outside group over analysis of tax framework MORE (R-Ky.) to oppose any short-term spending bill that includes funds for the healthcare law.

Congress will likely need to pass a spending resolution shortly after lawmakers return from the month-long August recess to prevent the government from shutting down.

Rubio said Republicans shouldn't support any funding measure that includes money to implement the healthcare law, including the new insurance exchanges set to launch on Oct 1.

“If this issue isn’t important enough for us to draw a line in the sand on, what issue is?” Rubio said.

Rubio said one of the reasons he opposes the implementation of ObamaCare is because is it “deeply hurtful to small businesses.”

“The impact this is going to have is not only will people lose their healthcare coverage, they're going to lose their hours,” Rubio said. “This is the real-world impact ObamaCare is having. This is terrible for our country."

The Obama administration has delayed for a year the employer mandate in the healthcare law, which requires businesses with more than 50 full-time employees to provide health insurance.

Republicans say the mandate will cause businesses to lay off workers and reduce hours in order to escape the requirements.