White House economic adviser Stephen Moore said Tuesday that the unemployment rate in April is higher than the 14.7% figure reported by the Bureau of Labor Statistics.

"The unemployment numbers are actually much worse than that headline number because they weren't counting millions and millions of workers who have been furloughed ... so we're probably closer to 20% unemployment rate right now," Moore told Hill.TV.

In April, an estimated 20.5 million jobs were lost due to the impact of the coronavirus.

Around 23.1 million people were unemployed in April, but this figure does not include unemployed Americans who have given up looking for work. CNN has calculated that in total, 43.2 million Americans were either out of work or working reduced hours in April.

"I think this summer is going to be brutally bad, it's going to be really bad in terms of businesses just trying to get their feet back on the ground, they'll be very slow to hiring workers back," Moore continued, arguing that the unemployment rate could easily reach 25%.

Moore, a supply-side economist, has pushed for payroll tax cuts to help workers affected by the crisis and derided government stimulus as an effective approach to help the economy. Moore has also urged states to loosen restrictions and open up non-essential businesses, while comparing stay-at-home protesters to Rosa Parks.

Moore believes that the U.S. could see an economic revival at the end of summer or beginning of fall. Treasury Secretary Steven Mnuchin has said 2021 could be a “great” year for the economy.

Like economic advisor Larry Kudlow, Moore was a regular contributor to CNBC. He helped the Trump administration draft the Tax Cuts and Jobs Act of 2017, slashing tax rates across the board. In March 2019, Trump nominated Moore to the Federal Reserve Board of Governors, but Moore withdrew his name weeks later due to backlash.