Treasury Secretary Steven Mnuchin predicted Tuesday that "massive tax reform" that includes cuts and changes to the system will get finished this year.

In an interview with CNBC, Mnuchin said the issue is his "No. 1 focus."

The Trump administration had been hoping to get the issue resolved before the August break. Mnuchin did not present that aggressive of a timetable, but said he is confident the administration and Congress can get reform accomplished.

"We're 100 percent committed to getting it done this year. It's critical to the economy," he said on "Squawk Box." "We have a unique opportunity to do this. It's been 30 years. We have to fix the system and our teams are meeting daily."

"We couldn't be more focused on getting this done," he added.

President Donald Trump has been pushing a three-pronged economic agenda: tax reform, regulatory rollbacks and infrastructure spending.

However, the initiatives have gotten held up amid disputes within the Republican majority as well as against the Democratic opposition, and as the administration has had to field congressional inquiries into the Trump campaign's ties with Russia.

Mnuchin said he believes tax reform will continue to make it through, despite the roadblocks. He envisions a reform program with widespread changes, including a territorial system giving companies a break for bringing back revenue earned overseas.

"The focus is lower rates. What comes with that is reform, which is broadening the base, making sure that we cut lots of special interest deductions, simplifying the tax code," he said.

"It makes no sense," he added of the current system. "We have one of the highest tax rates. We tax on worldwide income. We have a concept of deferral. We want to make sure that companies bring back that money onshore to reinvest in American equipment and American jobs."

Mnuchin confirmed that tax receipts have been coming in a little slower than usual this year as companies wait to see what happens with the reform process. That could take on added significant as Congress wrangles over raising the debt ceiling. The Treasury Department is taking measures to keep the government operating, but is on track to run out of money by early fall.

"We have plans to fund the government" through September or until Congress acts, Mnuchin said.