American corporations shouldn't expect to see tax reform from President Donald Trump until next year, CNBC's Jim Cramer said Tuesday.

"It has to be pushed back. It is too difficult," Cramer said on "Squawk on the Street." "First we have to do tariffs, ACA, tax reform. There [are] too many firsts."

Cramer's comments come amid a growing concern that tax reform could be pushed back a year.

Stocks and Treasury yields had jumped in the wake of Trump's Nov. 8 victory, amid the prospects for looser regulations in certain sectors, lower tax rates and fiscal stimulus.

Some of the delays appear to come from complications surrounding Republican attempts to repeal and replace Obamacare, according to a memo from FactSet.

In a Fox News interview that aired Sunday night, Trump said a replacement for Obamacare might not be ready until next year.

"You have to remember Obamacare doesn't work, so we are putting in a wonderful plan," Trump told Fox News' Bill O'Reilly.